The real reason for no 32gb option

[StayPuft]

Apple is not interested in making desktop replacements or gaming laptops.

This absolutely ridiculous statement is why people have convinced themselves that they're okay with mediocrity. Regardless of any weird statement you can possibly come up with, the 460 Pro is a budget card in a premium machine. A better GPU isn't for "gaming" ... all kinds of applications take advantage of a better GPU from editing, to rendering, to just about anything. Even Apple's own apps are "optimized" for the GPU ... such as Final Cut being optimized to take full advantage of the dual GPUs in the Mac Pro. People that want a better GPU in a Pro machine that costs 3 grand after taxes don't want it for gaming. They want it to optimize their Pro application experience. I'm literally dumbfounded that people can possibly think that's all a GPU is used for. This idea needs to die a horrible death. All that extra money you are paying for the laptop is not for any hardware in the machine, like every other laptop on the market. You are literally paying an imaginary "experience" tax that has nothing to do with the usability of the machine. It's absolutely insane. If the machines were priced according to hardware, people wouldn't be as pissed off, but the fact that you can pay that much for so little and people are okay with it is exactly the heart of the problem. Apple has convinced people this is okay.

 

[leman]

This absolutely ridiculous statement is why people have convinced themselves that they're okay with mediocrity.

Could you elaborate why my statement is ridiculous? Apple literally only ever used sub 50W mid-range GPUs in their MBP line. So again, they were never interested in making a gaming laptop or a workstation.

Regardless of any weird statement you can possibly come up with, the 460 Pro is a budget card in a premium machine.

Its quite far from being a budget card. Yes, its performance is a far cry from the much hotter desktop cards, but its not a budget card. Low yields and special manufacturing procedures make it far from being cheap. This is actually different from the other so-called pro cards, which the same chips as the gaming GPUs. The GPUs AMD makes for Apple undergo different manufacturing process than the 'normal' Polaris chips.

People that want a better GPU in a Pro machine that costs 3 grand after taxes don't want it for gaming. They want it to optimize their Pro application experience. I'm literally dumbfounded that people can possibly think that's all a GPU is used for.

Personally, I am using the GPU to prototype statistical simulations. I don't really understand why you would accuse me of claiming that GPUs are not of any use outside gaming.

Would I like to have a faster GPU? Certainly! Still, the MBP is what it is, and having a fast GPU is simply not possible with this particular design focus. Just as I wouldn't expect great battery life or portability from a gaming laptop, I don't understand how you can expect a hot GPU in a thin and light laptop that is optimised towards mobility. You simply can't have both with the limitations of the current technology.

All that extra money you are paying for the laptop is not for any hardware in the machine, like every other laptop on the market. You are literally paying an imaginary "experience" tax that has nothing to do with the usability of the machine. It's absolutely insane.

Now, that is an absolutely ridiculous statement. The experience tax is far from being imaginary. It gets me one of the best laptop displays on the market, fastest storage and I/O and top-tier mobility. All these things are very important to me. I don't care about having a fast GPU if this means that my battery life and portability need to take a significant hit. Yeah, thats 'experience'. I'd rather pay $3000 for a tool that does its job than $2000 for something that is useless to me.

And anyway, if you thing that the MBP is too expensive, simply don't buy it. I just don't understand why you have this urge for ridicule other people's choices.

 

[StayPuft]

Could you elaborate why my statement is ridiculous? Apple literally only ever used sub 50W mid-range GPUs in their MBP line. So again, they were never interested in making a gaming laptop or a workstation.

For the love of god, please stop equating a better GPU to a gaming laptop. The two are not mutually exclusive.

Its quite far from being a budget card. Yes, its performance is a far cry from the much hotter desktop cards, but its not a budget card. Low yields and special manufacturing procedures make it far from being cheap. This is actually different from the other so-called pro cards, which the same chips as the gaming GPUs. The GPUs AMD makes for Apple undergo different manufacturing process than the 'normal' Polaris chips.

It's a custom version of a very budget card ... bottom of the barrel in that line of Polaris chips. It's a budget card, end of story. There is no dancing around that, I'm sorry. It is what it is. Stop trying to convince yourself otherwise.

Personally, I am using the GPU to prototype statistical simulations. I don't really understand why you would accuse me of claiming that GPUs are not of any use outside gaming.

You said nothing to the contrary.

Would I like to have a faster GPU? Certainly! Still, the MBP is what it is, and having a fast GPU is simply not possible with this particular design focus.

And that's the problem. The design focus. Thinness is their top priority. What the Pro moniker actually symbolizes is now meaningless.

Just as I wouldn't expect great battery life or portability from a gaming laptop, I don't understand how you can expect a hot GPU in a thin and light laptop that is optimised towards mobility. You simply can't have both with the limitations of the current technology.

Again, you're making excuses for them to include a budget card in their machine. This chip is a custom version of their bottom of the barrel GPU line of Polaris GPUs. They chose to pick the absolutely crappiest one to have custom made for the MBP. On top of that, they had a custom made 450 version that's half as powerful ... so it's half as bad as an already low end budget GPU. They could have easily worked with AMD to have a custom version of the 470 or possibly even the 480 with a much lower heat and power output like they did with the 460. And ... at the very least ... they could have had it included as an upgradeable option. The biggest problem people have is there's absolutely no way of upgrading to anything better. That should be up to the customer. Not Apple thinking the only thing people care about is thinness and battery life. Having a better GPU with 5-7 hours of battery would appease many Pro users if it meant they could have more power.

Now, that is an absolutely ridiculous statement. The experience tax is far from being imaginary. It gets me one of the best laptop displays on the market, fastest storage and I/O and top-tier mobility. All these things are very important to me. I don't care about having a fast GPU if this means that my battery life and portability need to take a significant hit. Yeah, thats 'experience'. I'd rather pay $3000 for a tool that does its job than $2000 for something that is useless to me.

This is the definition of Kool-aid.

And anyway, if you thing that the MBP is too expensive, simply don't buy it.

And this is the statement that always debunks everything else you said. "If you don't like it, don't buy it!"

I just don't understand why you have this urge for ridicule other people's choices.

That's not what I'm doing. I'm ridiculing Apple. What you're ridiculing is my choice to object to their decisions in their product line. Get over yourself.

 

[leman]

And that's the problem. The design focus. Thinness is their top priority. What the Pro moniker actually symbolizes is now meaningless.

So much about a reality distortion field Apple's Pro laptops were always thin and light. Even in the time they were still called PowerBooks. I think you must be very confused. The fact is that Apple's design focus didn't change a least in the last 15 years or so. In a nutshell: make the most portable laptop with the best battery life while using the best available CPUs and best available low-heat GPUs. There was never a single MacBook Pro that attempted to do break this basic spec. In that regards, your arguments sound a bit silly. Where where you ten years ago when Apple was doing exactly what it is doing today?

 

[StayPuft]

So much about a reality distortion field Apple's Pro laptops were always thin and light. Even in the time they were still called PowerBooks. I think you must be very confused. The fact is that Apple's design focus didn't change a least in the last 15 years or so. In a nutshell: make the most portable laptop with the best battery life while using the best available CPUs and best available low-heat GPUs. There was never a single MacBook Pro that attempted to do break this basic spec. In that regards, your arguments sound a bit silly. Where where you ten years ago when Apple was doing exactly what it is doing today?

There's nothing confusing here. You're just drowning in Apple kool-aid. Apple's focus has changed significantly in the last 15 years. I don't know where you've been, but this reality of yours doesn't seem to align with actual reality. You can keep making all the excuses you want for what Apple does. But Apple does what Apple wants, regardless of what anyone else thinks. And they used to brag about their GPU power in their laptops compared to other laptops, but that's something you clearly don't remember.

 

[leman]

There's nothing confusing here. You're just drowning in Apple kool-aid. Apple's focus has changed significantly in the last 15 years.

Oh, so which one of this is a high-end GPU? The Mobility X1600? Or the 860M? Surely not the 9400M and the 9600M GT? Can you give us an example of Apple using a higher-end GPU in its laptop line?

P.S. Now, there was indeed a time when Apple was using Radeon 9*** GPUs for its PowerBooks (2002-2005). These were indeed among the fastest mobile GPUs on the market those days.

 

[bill-p]

So, what do YOU use your "Professional" system for? That is the question I originally asked. From Apple's business perspective, I don't see what the need for that much RAM is in a laptop. There just aren't enough users who would actually buy that much RAM to justify offering it. So, enlighten me.

Uhm... I'm hoping to be able to use my "Professional" MacBook to create, view and edit my panorama photos?

A typical photo output from my camera is a 50MP 14-bit RAW file (that's 14 bits per color channel in case you have any confusion).

I typically stitch together anywhere between 20 - 40 of them, but let's stay on the low side and say that I'm only stitching 25 shots together. That's...

25 x 50,000,000 x 3 (color channels) x 14 = 52,500,000,000 bits that need to be stored in memory all at once so the CPU can read and process the resulting panorama shot.

And the CPU needs to store the resulting panorama shot as well, right? So let's say the result is only 70% the size of the original shots because there are some overlap. That means it's...

52,500,000,000 x 70% = 36,750,000,000 bits necessary to store the finished panorama in buffer

So total memory usage for that panorama shot will be:

52,500,000,000 + 36,750,000,000 = 89,250,000,000 bits

In bytes = 89,250,000,000 / 8 = 11,156,250,000
In kilobytes = 10,894,775 kbytes
In megabytes = 10,639 mbytes
In gigabytes = 10.39 gbytes

So a MacBook with 8GB of RAM will thrash storage a lot when it tries to do that.

But imagine... I actually do 40-shot panoramas. When that happens, guess what?

40 / 25 = 1.6x more memory needed

Assuming same efficiency in panoramic stitching as above...

1.6 x 10.39 = 16.62 gbytes

That's just about the threshhold at which 16GB of RAM is no longer sufficient. And all of this would require that I only run photo editing apps, and nothing else alongside them. Do I see swap memory usage? Yes. A lot!

But what if I had used a 100MP camera instead? And what if such a camera comes with a new 16-bit RAW file format? Not even 32GB of RAM will be enough in that case.

Why do I need such massive resolution? For printing, and believe it or not, sometimes the client just wants bragging rights. Whatever the client requests, I gotta deliver, no matter how ridiculous it may be.

And all of that is purely memory-intensive. The processor really isn't doing that much more work at all.

On that note, ever since the switch over to "Retina", memory usage for all apps has skyrocketed, because Retina apps require higher resolution graphics, and I'm guessing extra memory buffer in order to scale the interface and texts of individual apps to 2x their original resolution before fitting to the screen (this is in order to work with scaling resolutions). I noticed I was very quickly running out of memory on 8GB even when I did not do much panorama work at all.

Even now, just running some usual apps for casual use, here are memory figures from highest to lowest, and I'm intentionally ignoring "kernel_task":

Lightroom 3.2GB <- just sitting there, viewing my photo library, not doing anything else
Firefox 2.66GB <- 2 tabs, I'm only using Firefox to view a website that does not work properly on Safari
Safari 1.00GB (base) + facebook.com (675MB) + slack.com (580MB) + macrumors.com (240MB) = 2.495GB

Total? 8.355GB

Just 3 apps, not counting anything else. Total of 5 browser tabs.

And 8GB is "enough"?

 

[maratus]

Make sure to go to other forums and complain about:

Quadro M1000M 4GB in Lenovo P50 (2.5kg, Quad Core)
Quadro M500M 2GB in Lenovo P50s (2.2kg, ULV Dual Core)
GeForce GTX 960M 2GB in Dell XPS 15 (2kg, Quad Core)
GeForce GTX 965M 2GB in Microsoft Surface Book with Performance Base (13.5" 1.65kg, ULV Dual Core)
FirePro W5170M 2GB in Dell Precision 7510 (15" 2.79kg, Quad Core)
Quadro M1000M 2GB in Dell Precision 5510 (15" 1.78kg, Quad Core)
FirePro W5130M 2GB in Dell Precision 3510 (15" 2.23kg, Quad Core)
FirePro W4190M 2 GB in HP ZBook Workstation Ultrabook (15" 1.9kg, ULV Dual Core)
Quadro M1000M 4 GB in HP ZBook Studio G3 (15" 2kg, Quad Core)
Quadro M600M 2 GB, Quadro M1000M 2 GB, Quadro M2000M 4 GB, FirePro W5170M 2 GB in HP ZBook 15 G3 (15" 2.63kg)

Only M2000M and GTX965M are on par with Pro 460 in terms of 3D performance with GTX965M being a bit faster at 2x power consumption. Actually both cards exceed Pro 460 TDP (M2000M not as much as 965M) and are less efficient. Both cards don't support dual 5K displays. All these laptops can be configured close to 15" rMBP. Many configurations are cheaper, some are more powerful (Quad-Core Xeons with 64GB ECC RAM option), but NONE of them provide the same package as rMBP 15". There're compromises in weight, processor, battery life, size (really!), screen quality, SSD speed, trackpads etc. Sometimes all these compromises are in the same laptop because typically you get what you pay for. So foreseeing unfair price comparisons – please do yourself a favour and analyze the whole package first.

Oh yeah, and make sure to provide a good 1.6...2kg 15" laptop with really powerful not-a-ripoff dGPU that real pros aren't ashamed to use (whether it's 4000$ or more, doesn't matter at this point)

 

[leman]

In bytes = 89,250,000,000 / 8 = 11,156,250,000
In kilobytes = 10,894,775 kbytes
In megabytes = 10,639 mbytes
In gigabytes = 10.39 gbytes

So a MacBook with 8GB of RAM will thrash storage a lot when it tries to do that.

What I am wondering about: is there any technical reason why you need to load the full image into the RAM? If I understand this correctly, what is happening is that the data is loaded, processed and then written to disk. Now, if you do it in chunks — say, divide the image into tiles and process these tiles independently, the overall time stays the same. You will still read, process and store the entire dataset exactly once. In fact, I can imagine that tiling could even offer some optimisation opportunities, because you could stream next tiles into RAM at the same time as the previous one is being processed.

 

[StayPuft]

Sometimes all these compromises are in the same laptop because typically you get what you pay for. So foreseeing unfair price comparisons – please do yourself a favour and analyze the whole package first.

So after analyzing the whole package, MBP's are still overpriced.

 

[maratus]

It's funny because there's no direct comparison with any of these machines. They're just very different and rMBP, for example, has unique features that could be a deal breaker regardless of price. It just was a trick question to make sure you don't understand the laptops' matrix of compromises.

 

[Howard2k]

And 8GB is "enough"?

lol at your trolling. A for effort.

 

[bill-p]

What I am wondering about: is there any technical reason why you need to load the full image into the RAM? If I understand this correctly, what is happening is that the data is loaded, processed and then written to disk. Now, if you do it in chunks — say, divide the image into tiles and process these tiles independently, the overall time stays the same. You will still read, process and store the entire dataset exactly once. In fact, I can imagine that tiling could even offer some optimisation opportunities, because you could stream next tiles into RAM at the same time as the previous one is being processed.

Yes, there is a reason tiling is not possible for panorama processing: the images may be out of order. So when you are processing panorama, you may choose, let's say, images 4-1-3-5-2

With that order, none of them will be interconnected and you won't be able to stitch them together.

A good algorithm will need all of the images loaded so that it can compare and connect the current image to all of the other ones.

In theory, yes, tiling would make things faster and more efficient, but there is just no solution to out of order images. You cannot sort them either, because until the computer has scanned all of the images and mapped them, it won't know which one is 1 and which one is 2.

The buffer is also somewhat necessary for the computer in order to write to and read from in order to verify that it has done its job. Granted, you can probably write and then read this buffer on the hard drive, but that's just going to be exactly what the swap file is supposed to do anyway. Having more memory in this case will also significantly speed things up.

The whole point of having a lot of memory is simply so that you can use it as faster storage than whatever the other solution is (SSD?). It defeats the purpose if you have to use your hard drive in order to make up for the memory deficit.

See how well that has worked out for iOS?

As an aside, I can't even display and zoom in to some of my panorama shots on an iPad Pro 9.7" because it just doesn't have enough memory for the uncompressed data, and tiling from storage apparently just doesn't work that well for JPGs over 300MB in size. The 12.8" is just barely able to do that.

 

[moosington]

There's nothing confusing here. You're just drowning in Apple kool-aid. Apple's focus has changed significantly in the last 15 years. I don't know where you've been, but this reality of yours doesn't seem to align with actual reality. You can keep making all the excuses you want for what Apple does. But Apple does what Apple wants, regardless of what anyone else thinks. And they used to brag about their GPU power in their laptops compared to other laptops, but that's something you clearly don't remember.

Have you looked at every unibody MBP that's been released? They all offer very similar specs. There's literally nothing surprising about the specs of the new MBPs. They brag about all their specs. Did you see them tout 2x graphics performance boost this generation? Nothing new. The new generation of MBPs is a refinement of the previous. You say that people are just drinking the koolaid, and that Apple has just changed, but what were they doing before that was drastically different?

I don't even know where these expectations came from. It got thinner, lighter, slightly more powerful, dropped things Apple thought was useless, redesigned a user interface (TB), improved the hell out of the screen/trackpad/ssd speed, and the battery has dubious results on the TB model. All of that's pretty normal for a new gen Apple product.

Also stop using "you're just a koolaid drinker!" as a counter argument. It's dickish, shuts down discussion and screams "I can't properly defend my point."

 

[paaj]

Panorama could work starting with smaller hashes of the images to calculate the right order (the photo deduplicator I use does this to compare 25k+ images fast) but this may be one of the situations where more than 16 is preferred.
Still, not many comparable machines available that do offer 32, previous versions also maxed out at 16 and I'd do this at a desk anyway. and maybe a half-res preview on-site is good enough to demonstrate the result.

 

[maratus]

that Apple has just changed, but what were they doing before that was drastically different?

Apple indeed has just changed. They haven't offered a workstation dGPUs in their laptops before. And I don't recall them giving 3 configuration options. It's the first time dGPU in a MBP 15" is so capable in handling external displays. And 4GB or VRAM is the first time dGPU is MBP 15" is actually on par with almost any other current workstation laptop offering and not 2x behind like it used to be. Very few provide 6GB or 8GB VRAM nowadays.

Of course some people complain about driver support for hardware acceleration and lack of CUDA, hopefully it'll be better in future. Apple definitely wants to stick with AMD cards in all their products...

 

[slughead]

No, it was a serious question. I don't know what workloads would require that much RAM in a laptop. Evidently, Apple doesn't think there are enough potential buyers for 32 GB to warrant offering it.

I totally agree, like I said: this ultraportable has 2008-level GPU, a laughable amount of internal storage, and a tiny battery. Any workload that would require 32GB of RAM would almost certainly be limited by these other factors. You hit the nail on the head: with this laptop and these limitations, it makes no sense to have 32 GB.

An Alienware R2 15", for the same price as the 15" rMBP, however, has >3 times the GPU speed (980m), a 2.5" slot (up to 4TB, baby!), m.2 slot (max 2tB), 15" touch screen at 4k, SD reader, gigabit ethernet, does not thermal-throttle, oh yeah, and 32GB max ram. It's a desktop in a laptop.

Ultraportables are just glorified iPads for twice the price and in Apple's case, a lot less battery life. Why put 32GB in there? It's like having a 30 gallon gas tank on a vespa.

Edit: also, I agree with others that point out that even with this lack of performance, this is a step-up for Apple. However other manufacturers are offering real workstation laptops with a ton of power in a portable package--for the same price. Lugging a laptop twice as heavy and thick is apparently not a big deal for people who want real power in a portable package. A recent study by Intel does not even call these "gaming" laptops, they call them workstations. Macbook pro does not fit that description at all.

 

[zhenya]

I totally agree, like I said: this ultraportable has 2008-level GPU, a laughable amount of internal storage, and a tiny battery. Any workload that would require 32GB of RAM would almost certainly be limited by these other factors. You hit the nail on the head: with this laptop and these limitations, it makes no sense to have 32 GB.

An Alienware R2 15", for the same price as the 15" rMBP, however, has >3 times the GPU speed (980m), a 2.5" slot (up to 4TB, baby!), m.2 slot (max 2tB), 15" touch screen at 4k, SD reader, gigabit ethernet, does not thermal-throttle, oh yeah, and 32GB max ram. It's a desktop in a laptop.

Ultraportables are just glorified iPads for twice the price and in Apple's case, a lot less battery life. Why put 32GB in there? It's like having a 30 gallon gas tank on a vespa.

Statements like this show how out of touch you are with the vast majority of people who actually make a living with their laptops. For the vast majority of them they want something that is light enough to easily carry it (because it will be going with them every day for years) and the more battery life, the better. An 8lb gaming laptop appeals to what amounts to effectively zero successful professionals that you will see in the Business Class lounges in airports around the world, or in the conference rooms of anything but the companies that make the games targeting the Alienware demographic.

 

[JohnnyGo]

Statements like this show how out of touch you are with the vast majority of people who actually make a living with their laptops. For the vast majority of them they want something that is light enough to easily carry it (because it will be going with them every day for years) and the more battery life, the better. An 8lb gaming laptop appeals to what amounts to effectively zero successful professionals that you will see in the Business Class lounges in airports around the world, or in the conference rooms of anything but the companies that make the games targeting the Alienware demographic.

+1

I would also add that the sales/success of the retina MacBook is proof that "professionals" are going in the opposite direction of the whiners: LESS IS MORE NOWADAYS. People are realizing they don't need that much CPU, they can play games on their phones or tablets, and if and when they need heavy lifting they can always enjoy a cup of coffee or listen to a podcast.

It is true that Apple could produce a "pro" laptop to be a true desktop replacement but that was never Apple's goal.

 

[dan9700]

No one needs 32 even in a high ending gaming pc 16 is enought as most of the time the graphics vram is more important

 

[slughead]

Statements like this show how out of touch you are with the vast majority of people who actually make a living with their laptops. For the vast majority of them they want something that is light enough to easily carry it (because it will be going with them every day for years) and the more battery life, the better. An 8lb gaming laptop appeals to what amounts to effectively zero successful professionals that you will see in the Business Class lounges in airports around the world, or in the conference rooms of anything but the companies that make the games targeting the Alienware demographic.

Yes, the majority don't need a powerful GPU for work, that's why tablets are outselling laptops by a huge margin. Some people DO need a real GPU, SD card reader, hard drive space in a laptop--particularly those who would pay $2,500 for a machine. Maybe they're using adobe premiere or do raw photo work. Statements like these show how out of touch you are with anyone who does need a GPU with more power than those released in 2008. Some of us also need hard drive space.

I like how you carefully qualify "out of the professionals I see who are in business lounges, I never see a thick laptop." Yes, thank you, there are people who actually use the power of their computer to run applications that demand it as well.

Essentially you're attempting to imply by your post that anyone who needs a GPU with more power than those created prior to Obama being elected (yes, THAT's how long ago 2008 was) cannot be a professional. By the way, did you know the 450 radeon is only like 25% faster (by tflop) than the Iris Pro graphics in the macbook pro? Screamin'!

If you want a sleek-looking machine for email and you have too much money, you're right, this fits the bill (albeit way overpriced). You could just get a keyboard for your iPad though--and MOST people are doing that. This is thin and light, but the main selling point is this plus the status symbol and the fact that it looks cool (no arguments there!).

 

[lockerc18]

Yes, there is a reason tiling is not possible for panorama processing: the images may be out of order. So when you are processing panorama, you may choose, let's say, images 4-1-3-5-2

With that order, none of them will be interconnected and you won't be able to stitch them together.

A good algorithm will need all of the images loaded so that it can compare and connect the current image to all of the other ones.

In theory, yes, tiling would make things faster and more efficient, but there is just no solution to out of order images. You cannot sort them either, because until the computer has scanned all of the images and mapped them, it won't know which one is 1 and which one is 2.

The buffer is also somewhat necessary for the computer in order to write to and read from in order to verify that it has done its job. Granted, you can probably write and then read this buffer on the hard drive, but that's just going to be exactly what the swap file is supposed to do anyway. Having more memory in this case will also significantly speed things up.

The whole point of having a lot of memory is simply so that you can use it as faster storage than whatever the other solution is (SSD?). It defeats the purpose if you have to use your hard drive in order to make up for the memory deficit.

See how well that has worked out for iOS?

As an aside, I can't even display and zoom in to some of my panorama shots on an iPad Pro 9.7" because it just doesn't have enough memory for the uncompressed data, and tiling from storage apparently just doesn't work that well for JPGs over 300MB in size. The 12.8" is just barely able to do that.

Interesting. Thanks.

I can see that there are SOME users, like you, out there who have a need for 32GB. But how many are there who want this much in a laptop? And, are there enough to warrant Apple offering 32GB in a MBP? Apple evidently doesn't think so.

I believe Apple has segmented this high end RAM requirement around the Mac Pro. Sure, that's not portable, but it's plenty powerful for these kinds of apps. So, from Apple's perspective, it's not how much RAM you need in your system that determines what it offers. It's what form factor is appropriate for that much RAM (or more) and other capacity requirements. YMMV, of course. This doesn't apply to every user. But I can see Apple planners doing a segmentation analysis to determine their product set, and saying that very resource consumptive workloads appear mostly in a desktop user community, so Mac Pro is the best platform for them. Whereas such high end requirements aren't as pertinent to a mobile community.