Does Cache on the new penryn really matter?

[FreAk6767]

Hello,

Though I'd drop in, to ask you guys this:

I currently have a MBP 2,33Ghz C2D (purchased in March 07), with 2Go Ram.

For various reason I can sell it for a very good price (1500€), and therefore was planning on getting one of the new MBP.

I looked at the base model, the 2,4Ghz and the 2,5Ghz.

I know that in both case, compared to what I've got, it won't be a massive change! I know that.

However, I'm concerned about the cache thing between the 2,4Ghz which is L 3Mo, and the 2,5Ghz that seems to be 6Mo.

Is it really worth it to go for the 2,5Ghz and its 6Mo cache?

I believe my 2,33Ghz C2D is 4Mo cache, would the new base model be less powerfull?


I know this wasnt a really big update, but for 1797€, I'd go from a 2,33Ghz C2D, 2GoRam, 120Go @5400, non led screen, to the 2,4Ghz Penryn, 4Go Ram, 200Go @7200, glossy/led screen.

I can't really go wrong for 297€?

and I mainly work on CS3 and Logic Pro, so that's my life in that aluminium box! lol

Thanx for your wise and useful advises.

F.

 

[TraustiB]

You would definately feel a little speed bump if you go with 4gb of RAM and the 7200RPM drive + 512MB graphics card form nVidia and 2.5ghz 45nm processor wont hurt either

I''ve got the 2.16ghz version you have, with the x1600 graphics card, although you've got 256mb but me only 128mb. I'm seriously considering upgrading, for the multitouch, hopefully less heat and all around snappier system.

For the money you pay I think it would be worth it IMHO. We're on the same boat pretty much. I'm getting a great price for mine so the change won't be too painful

 

[jbg232]

For 300 that sounds like a pretty nice set of upgrades. The hard drive is faster (sometimes this affects performance more than the cpu - ie when opening programs), the screen is nicer and brighter, and the memory is the best part of all (although you could get cheaper memory from crucial). Specifically about the cache, I would say the difference between a 2.33 and a 2.5/2.6 MIGHT be noticeable, but the the 2.4 upgrade will not be noticeable because as you said it has LESS cache. The only time penryns will always perform better is on media applications that specifically engage the SSE4 instruction set (ie decoding video). Aside from that, you won't notice it. In the end though, I say its worth it, but what do we know, it's not our money.

 

[FreAk6767]

So,

The cache difference with my "old" MBP 2,33Ghz and the new base model 2,4Ghz penryn, won't be that important? Or its gonna drive down the performance?

For the post above, I said i was gonna get 4Go Ram, but of course not from Apple, but Crucial or similar shop.

 

[jbg232]

So,

The cache difference with my "old" MBP 2,33Ghz and the new base model 2,4Ghz penryn, won't be that important? Or its gonna drive down the performance?

I doubt you'll notice it unless video encoding tasks or other sse4 enhanced tasks (which there are very few right now).

 

[Lyshen]

3 MB vs 4 MB vs 6 MB cache... it all comes down to what you do and your budget.

For most people the other components, ram amount and HD (size/speed) are probably more important.

In terms of performance, there is a small difference but it isn't that noticeable for the most part. One example of where bigger cache helps but not many do this... using Folding @Home.

 

[wrightc23]

In all honesty I think you'd probably be disappointed, unless you spend a substantial portion of your time encoding with an SSE4 compatible application I doubt you'd see much difference.

Architecturally the 2.33 and Penryn 3.4 are from exactly the same family. The Penryn is just a couple of iterations newer but basically the same processor.

Spend some money on more RAM or a quicker HDD for now.

I'd seriously suggest that MacBook Pro owners with anything newer than the original 32bit Core Duo model MBP will not be able to tell the difference in performance between any of the Core 2 Duo MacBook Pro generations.

 

[HLdan]

Specifically about the cache, I would say the difference between a 2.33 and a 2.5/2.6 MIGHT be noticeable, but the the 2.4 upgrade will not be noticeable because as you said it has LESS cache.

Then you don't understand how cache works. Cache does not add speed increase in performance, it's specifically for launching applications. Intel already uses much more cache in their processors than needed, at this point it's more of a marketing ploy. 1-2MB of on die L2 cache is all that's needed unless you plan on opening at least 10 apps at once then closing them all and then relaunching then more cache is welcome for speedier re-launches but it has no bearing on speed increases when it comes to processing.

 

[DocSmitty]

Any of the new processors will be superior to the one you have now, and for 300 euros that upgrade is a bargain.. do it!!!!

As far as benchmarks go:
2.1/3mb --> 2.4/3mb is about equal to
2.4/3mb --> 2.5/6mb

So either the cache is making a ~.2 ghz difference or there is some other difference between the chips. These benchmarks were not taken from the MB/MBP, they were all done on the same system so it's not RAM/HDD/VRAM making the difference.

 

[FreAk6767]

Any of the new processors will be superior to the one you have now, and for 300 euros that upgrade is a bargain.. do it!!!!

As far as benchmarks go:
2.1/3mb --> 2.4/3mb is about equal to
2.4/3mb --> 2.5/6mb

So either the cache is making a ~.2 ghz difference or there is some other difference between the chips. These benchmarks were not taken from the MB/MBP, they were all done on the same system so it's not RAM/HDD/VRAM making the difference.

Indeed, 300€ is quite good for an update, selling the 2,33Ghz at 1500€ sure helped.

I'm still a bit confused.
The logic would be that the base model penryn performs at least as well as my old 2,33Ghz. If its not the case, then I would go for the 2,5Ghz with its "Cache 6mo"! lol

But to be fair, my 2,33Ghz is a good machine, but what I'm gonna feel the most is a 7200 HD and the 4Go compared to now. Illustrator and Photoshop is putting the MBP2,33Ghz on its knees with files>400Mo.

Logic Pro: can't really complain, but the update won't hurt either.

(on side, purchasing a new MBP gives a new warranty that just expired on the other one, a led screen, hummm, multitouch hummm,)

Maybe I'm just worryin too much!

 

[jjahshik32]

yes it cache size DOES matter, no wonder the 2.4ghz penryn is cheaper than the sr 2.4ghz, its crippled by 3mb of cache .

 

[DocSmitty]

Expect the processor to be about equal with what you have now. They are better, but probably not noticeably so.

However, you are getting a slightly better processor PLUS all the other goodies for that price. That's why I think it's a steal. I wouldn't worry about upgrading to the 2.5 unless you can afford it and want the extra Video RAM.

 

[FreAk6767]

Expect the processor to be about equal with what you have now. They are better, but probably not noticeably so.

However, you are getting a slightly better processor PLUS all the other goodies for that price. That's why I think it's a steal. I wouldn't worry about upgrading to the 2.5 unless you can afford it and want the extra Video RAM.

I don't play games at all. (there's console for that i think)
No final cut or encoding video either (at least not at high level, probably some iMovie sometimes)

But Photoshop and Illustrator are nearly on 24/7 for my design job. (would that require the extra 512Vram? I don't think so, and Logic studio wouldnt either, i think)

Like you say, with all these goodies, I agree it seems like a steal to me too.

Great help, appreciated! (or am I just happy because I heard what I needed/wanted to hear? lol)

 

[HLdan]

yes it cache size DOES matter, no wonder the 2.4ghz penryn is cheaper than the sr 2.4ghz, its crippled by 3mb of cache .

YES, cache being bigger on one model of the other makes a difference but the amount of cache the Intel processors have at this point is much more than needed for most apps so it's not something for anyone to get worked up about.

 

[Radio Monk33]

yes it cache size DOES matter, no wonder the 2.4ghz penryn is cheaper than the sr 2.4ghz, its crippled by 3mb of cache .

Just because you say it doesn't mean it's true. Do you have any evidence at all that it is "crippled"?

 

[PenrynMBP]

tests already proved that the 2.4ghz 3MB Cache out performs or equal to the previous 2.4ghz 4MB Cache SR.

 

[Salty Pirate]

I type this on my new 2.4 GHz cripplecache......


I honestly cannot say this machine is slow. Very snappy. Better or equal to my old SR 2.4 15. Tomorrow I get my Kingston GB RAM, then we will really see.

 

[wk127001]

A larger cache will increase the average memory access time of your system. However that depends on how well your OS utilizes it, OS X fortunately does this well. Will a 1MB be noticeable however? Probably not. But if you're real worried about it, get the 2.5GHz model which has a larger cache and more graphics memory. The larger graphics memory will be a big bonus especially if you use an external display with high resolutions.

 

[CanadaRAM]

Then you don't understand how cache works. Cache does not add speed increase in performance, it's specifically for launching applications. Intel already uses much more cache in their processors than needed, at this point it's more of a marketing ploy. 1-2MB of on die L2 cache is all that's needed unless you plan on opening at least 10 apps at once then closing them all and then relaunching then more cache is welcome for speedier re-launches but it has no bearing on speed increases when it comes to processing.

I can't agree with you there. You may be confusing L2 cache on the CPU with ReadyBoost, or hard drive caching. Every access to memory, whether it is application code or data, is cached in the L2 cache for higher speed access when returning to the same lines of code or data repeatedly (which most computer programs do) http://en.wikipedia.org/wiki/L2_Cache
In fact the one time a L2 cache does next to no good is when loading an application, because none of the app will be in the cache to hit.

CPU caching can significantly improve the performance of a machine, especially when the processor capability outruns the speed of the RAM memory.

 

[Animalk]

"Cache is nothing but a performance cruch for poor chip design."
- My computer architecture teacher.

For those that don't understand this clearly:
Think of Cache as the displacement (litres) of a particular car engine. People often associate large displacement with more power(hp and especially torque), it is often not the case.

Each chip has an optimal amount of cache to assure optimal throughput of the CPU(s) inside the processor. Adding anymore cache is almost useless from that point on.

So the question is, what is the optimal cache size for this particular chip?

 

[PenrynMBP]

"Cache is nothing but a performance cruch for poor chip design."
- My computer architecture teacher.

For those that don't understand this clearly:
Think of Cache as the displacement (litres) of a particular car engine. People often associate large displacement with more power(hp and especially torque), it is often not the case.

Each chip has an optimal amount of cache to assure optimal throughput of the CPU(s) inside the processor. Adding anymore cache is almost useless from that point on.

So the question is, what is the optimal cache size for this particular chip?

So your saying MORE CACHE does not necessarily mean it is better?
Cause like I am upset that I am getting the 3MB Cache Penryn which is less than the 4MB Cache Santa Rosa.
And I will be using it for Video Editing a lot. I don't care about power efficiency saving.

 

[Animalk]

So your saying MORE CACHE does not necessarily mean it is better?
Cause like I am upset that I am getting the 3MB Cache Penryn which is less than the 4MB Cache Santa Rosa.
And I will be using it for Video Editing a lot. I don't care about power efficiency saving.

That is correct. Cache is very expensive. Adding more then you need would be suicidal for a processor company. It would also be suicidal for a processor company to build a processor that is significantly starved from not having enough cache.

Now I have not read the cold hard spec sheets of these processors yet as I don't have the time to put in the research but it is highly unlikely that Intel is short changing you. So i cannot say for certain if Intel and Apple are short changing their buyers in this case.

I must first define the term "throughput". Throughput is how much work the processor is getting done. Inside the processor there is Cache and there is CPU. Cache is memory and CPU is brains. Think of the Cache as an office desk and think of CPU as a secretary. The bigger the desk the more room she or he has to manage all her papers and work.
So the main idea is if you have a really smart secretary (CPU), then he or she can work optimally on a relatively small desk (Cache).

You have a 100mhz difference in processor speed between a chip with 3MB cache and a chip with 6MB cache in this particular case. Now this is surprising. Why double the cache for only a minimal increase in processor speed (i.e. a minimal increase in throughput). Well thats because in chip design they increase the amount of cache by shrinking them and then putting mirrors of them next to each other. Just like cores. So once they reach the limit of a particular cache, they usually double it. Then you ask why not put just one more smaller cache and not have two mirror caches? Isn't cache expensive? Yes, but so is making two different chips with only a little more cache in one and double in the other! So they essentially double the cache the second they reach a limit and stay with that size until they reach that new limit.

I hope this clears things up for some of you. This is how my Computer Hardware teacher taught it to me.

 

[jbg232]

^^^^^^^ Really good post, I like the economics behind it, I never thought about that before.

 

[PenrynMBP]

That is correct. Cache is very expensive. Adding more then you need would be suicidal for a processor company. It would also be suicidal for a processor company to build a processor that is significantly starved from not having enough cache.

Now I have not read the cold hard spec sheets of these processors yet as I don't have the time to put in the research but it is highly unlikely that Intel is short changing you. So i cannot say for certain if Intel and Apple are short changing their buyers in this case.

I must first define the term "throughput". Throughput is how much work the processor is getting done. Inside the processor there is Cache and there is CPU. Cache is memory and CPU is brains. Think of the Cache as an office desk and think of CPU as a secretary. The bigger the desk the more room she or he has to manage all her papers and work.
So the main idea is if you have a really smart secretary (CPU), then he or she can work optimally on a relatively small desk (Cache).

You have a 100mhz difference in processor speed between a chip with 3MB cache and a chip with 6MB cache in this particular case. Now this is surprising. Why double the cache for only a minimal increase in processor speed (i.e. a minimal increase in throughput). Well thats because in chip design they increase the amount of cache by shrinking them and then putting mirrors of them next to each other. Just like cores. So once they reach the limit of a particular cache, they usually double it. Then you ask why not put just one more smaller cache and not have two mirror caches? Isn't cache expensive? Yes, but so is making two different chips with only a little more cache in one and double in the other! So they essentially double the cache the second they reach a limit and stay with that size until they reach that new limit.

I hope this clears things up for some of you. This is how my Computer Hardware teacher taught it to me.

Thanks a lot Animalk! its clear to me now, I can't wait till my MBP arrives!

 

[Animalk]

I am glad I was able to help you and hopefully others in the future.

I highly doubt you will see a significant or "worth mentioning" performance increase in the two models. I actually highly doubt that giving up your current MBP for a new one is really worth your troubles in my honest opinion.

I have the lower end model of the same MBP revision as you and I cannot tell a difference between it and my friends newer MBPs. I also believe the picture the LED screen's isn't as good as the lamp ones in yours and mine (when they are working properly with no yellowing or bands ).

I have never done any video editing or encoding but highly doubt upgrading your machine will give you a performance increase worth your troubles. The battery life isn't much different either from what I have seen.

Regardless, good luck in your decision.