More than 4GB RAM in latest iMac 3.06 ?

[dukebound85]

Apple is pretty notorious for understating the max amount of ram their computers can use. I had 3GB in my macbook (and do in my work computer - a macbook) for a year with no ill effects, despite apple's statement that the computer couldn't handle more than 2GB.

the core duo machines can only take 2 gigs max so it is right for some macs

 

[fredsarran]

Good to know !

So how many people here thinks that putting 8GB in a iMac 3.06 will work and make a difference ?

Anybody rich enough to try out ?

 

[Cabbit]

Can anyone confirm that if it works under a MacBook Pro, then it should work on the iMac 3.06 ?

Could you please give me the specs of your MBP ? Does the system profiler detects your extra RAM ? Do you notice a performance boost ? How about the heat and fans of your MBP ?

Thanks for your posts, it gives me hope

The clients Macbook pro seen the full amount of ram in system profiler and activity monitor.
I did not run any tests on performance and in general the machine felt slower than my Macbook which i would put down to the 5400rpm hard drive vs my 7200 rpm, there were no memory intensive tests done on the system.
Without 64 bit apps it is very difficult to get performance out of 8GB's of ram i see it being useful when opening huge Photoshop files or for video work though without these apps being 64 bit the benefit may not be seen.

 

[bentoms]

ah.. may have solved it!!

check this post from mac osx hints

Thanks for the link, BandgerUMD. I did read that link earlier this week and I think it was prompted me to purchase the RAM for $100 even if it could only address 3.3GB.

Macavenger's comment on the link BadgerUMD provided explained it well:Ok, people, here's how this works. While the processor in older macbook pros is 64 bit, the chipset used to access the memory is only 32 bit (as mentioned in a previous post). This 32 bit limitation implies that it is only capable of addressing 2^32 bits=4294967296 bits=4 Gbit 1-byte memory locations, or 4 GBytes of ram (each of the 4 Gbit memory addresses is 1 Byte of actual RAM)

Now computers typically use what is called Memory Mapped I/O, which means that you send data to/from input or output devices by writing that data to a specific memory address which is mapped to the I/O device in question. This is done so that all data transfers look the same to the computer, and don't require any special programing-a read from ram is exactly the same (to the CPU) as a read from the hard drive, it's just looking at a different "memory" address that happens to be connected to a physical device. This is somewhat simplified, of course, as it has to address the proper area of the hard drive, but that is handled at a different level.

In order to make this work, a portion of that 4 GB memory space addressable by the memory controller chip has to be set aside for I/O operations - specifically the upper 700 some odd megs. There is nothing to prevent you from putting in 4 GB of RAM, rather than 3, nor will doing so cause any problems, and as the hint says the computer will SEE that you have 4 GB installed. However, this does not change the fact that it is unable to USE all of it for RAM. Apple could have said the machines supported up to 4 GB, and they would have been technically correct, as the system will "see" all 4 GB. This is, in fact, what many PC manufacturers do. Apple chose instead to claim only 3 GB supported in order to keep people from wasting their money buying extra RAM their computer would be unable to use.

Newer laptop machines (I'd have to check which models specifically) use the 64bit santa-rosa chipset, which being 64 bit can address MUCH more memory, effectively removing the 4 GB limitation. There is still a physical limitation as to the size of the ram chips and how many you can fit into the machine, of course, and there may be other limiting factors, but the addressable memory limitation is gone (at least for a while).

There. I knew that Computer engineering degree I worked so hard for would come in handy sometime.
OWC has some nifty testing of various apps and benchmarks to see how different quantities of paired and unpaired RAM faired. In every result 4GB was the faster.• http://eshop.macsales.com/shop/Memory_Benchmark/Apple_MacBook/
vBulle

So on my WHITE 24" iMac it can only address 3.3GB of RAM, due to the limitations of the 32bit (READ: 4GB) memorary address available.

If your's is a new aluminium iMac then you should have a 64 bit memorary address availabled which means that 8GB will be available.

 

[netherfred]

Of course they will sell you a second car

Apple isn't going to try to sell you an upgrade that costs more than your computer.

Except for the Mac Pro, where 16Gb of RAM is one and a half times more expensive than the base configuration tower...

 

[fredsarran]

So it works ?

So, based on the above, iMac 3.06 is a 64 bit machine (please correct me if I am wrong) and officially can only hold 4GB of RAM. But because it is a 64 bit, it can hold up to 8GB.

So recognizing the amount of memory, by the iMac, and fitting it in is not a problem.

Based on another post, you do not notice a speed increase in everyday use of the iMac but if using Apple Pro apps or others, it would be a huge benefit (beside the price of the RAM).

I would love to hear more from other. I think Apple should put this 8GB upgrade as an option when buying the iMac.

What do you think then ? Is it worth it ? I use Pro apps and would like to play games that will benefit from more RAM. But it is a risk, maybe it will not work and that is then £500 of RAM flushed away.

Please let me know And if someone can bring up a test and/or review that would be top

 

[Cabbit]

So, based on the above, iMac 3.06 is a 64 bit machine (please correct me if I am wrong) and officially can only hold 4GB of RAM. But because it is a 64 bit, it can hold up to 8GB.

So recognizing the amount of memory, by the iMac, and fitting it in is not a problem.

Based on another post, you do not notice a speed increase in everyday use of the iMac but if using Apple Pro apps or others, it would be a huge benefit (beside the price of the RAM).

I would love to hear more from other. I think Apple should put this 8GB upgrade as an option when buying the iMac.

What do you think then ? Is it worth it ? I use Pro apps and would like to play games that will benefit from more RAM. But it is a risk, maybe it will not work and that is then £500 of RAM flushed away.

Please let me know And if someone can bring up a test and/or review that would be top

64 bit machines can have upto 16 exabytes of ram, unfortunately Intel believes the Santa rosa chip set of being capable of only 8GB of ram at the moment as there are no larger so-dimms than that available.
Apple set the limit at 4GB because at the time there were no larger so-dimms than 2GB available.
So end be all end of is that you can have 2x4GB of ram for a maximum of 8 GB of ram.

 

[eXan]

What do you think then ? Is it worth it ? I use Pro apps and would like to play games that will benefit from more RAM. But it is a risk, maybe it will not work and that is then £500 of RAM flushed away.

What "Pro apps" do you use? How intensively? What are the specs and page-in/page-out readings on your current computer? Do you easily max out 4 GB RAM (assuming you have 4 currently)?

P.S.: there's no difference for a modern game whether your system has 2 GB RAM or 4. What makes you think having 8 GB would be beneficial?

Just trying to figure out if your actually need 8 GB...

 

[DaftUnion]

Alright, since this hasn't been stated yet, your computer is going to run at the same speed if you only have a few apps open regardless if you have 4gb of memory or 400gb of memory if there was such a thing.

So to save you some money, for a reasonable amount of apps open more memory over 4gb will get you hardly any...if any speed boost at all.

The only thing memory does is let you have tons of applications (or memory intensive ones) open at once and let you switch between them quickly without the system slowing down. I can't possibly think of seeing a night and day...or even a noticable difference between having your system maxed out at 4gb or trying the 8gb instead.

Regardless of what you try, the money you'll put into trying to get the machine to go to 8gb instead of the cheaper 4gb route is not going to be worth it. I have friends that are heavy duty photoshop/final cut users and with 4gb that machine NEVER gets bogged down.

 

[munckee]

the core duo machines can only take 2 gigs max so it is right for some macs

I'm well aware. However, when they moved from Core duo to Core 2 Duo machines, they didn't raise the ram limit stated (until machines could use 4GB).

 

[Elven]

For all we know this "could" be part of an iMac refresh

 

[fredsarran]

I had a iMac 2.8 with 4GB of RAM, and at times when I had a few things open, it would slow down.

I do not always have a lot of money to spend on a new Mac, that is why I am also looking at Mac Pro for long term. iMac are great but not expandable. If I know that 8GB would work, then I would invest in a iMac and buy the 8GB later when the price drops.

I believe that 8GB should make a difference for games and the Pro apps (I use most of Apple Pro apps and Adobe CS3 apps).

 

[molintorch]

as far as gaming goes, almost no games are written for 64 bit at this point (assuming you are bootcamping into windows), so I would rule that logic out for now. The only exception might be Age of Conan, which supposedly shipped with both a 32 and 64 bit client installer on the dvd set (though I didnt try).

Also, gaming support for 64 bit windows (Xp or Vista) is horrible at best. Drivers are scarce, Video card support is lacking, etc. Unless you are going to run a 64 bit version of windows, then the same 3.x gig of memory limit is going to kick in, and you will have wasted your $$ for the extra ram.

Currently I am running my 3.06 with its stock 2 gigs and it runs great, no slow downs, no issues. I spend 75% of my time in OSX and 25% in Vista for gaming. At the most, 4 gigs is all you will need for current games today, but really, 2 gigs is more than enough. What you really need is a strong video card which the latest iMac offering resolved (ie the 8800M GTS rocks for gaming ).

Hope this helps, just keep in mind what your intent is. For the most part, we wont see 64 bit games until two things happen really, good OS support for 64 bit and Console support for 64 bit (if you noticed, tons of games now are written for a single console, the ported to other platforms). later!

 

[eXan]

I had a iMac 2.8 with 4GB of RAM, and at times when I had a few things open, it would slow down.

this is useless without your page-in/page-out numbers

 

[26139]

Yeah, but

If you're doing something that requires 8 gigs of ram, wouldn't you be better off with a Mac pro?

 

[fredsarran]

Cheers.

Thanks for your post. May I ask what games you are running and at what settings ?

 

[fredsarran]

this is useless without your page-in/page-out numbers

How do I find that out ? Also I sold my iMac 2.8 already.

 

[fredsarran]

If you're doing something that requires 8 gigs of ram, wouldn't you be better off with a Mac pro?

I would love to get one but it is really more expensive and I still need to get a screen.

 

[molintorch]

Thanks for your post. May I ask what games you are running and at what settings ?

Currently installed
-Age of Conan
-Team Fortress 2
-Halflife 2
-Portal (Companion cube!!!)
-Call of Duty 4
-World in Conflict

I'm running Win Vista 32 bit Home Premium, Nvidia beta drivers 175.80, 100 gig partition, native resolution in each game (1920x1200), and max settings except in AoC which I turned off Shadows only. If you search around this forum, you will also find some posts where I did a few initial benchmarks as well for gaming performance (if you want details).


Note about Nvidia drivers... being that the 8800M GTS is technically a mobile video gpu, you will not be able to download drivers from Nvidia web site and have them work. While the default apple driver makes the OS think the card is an 8800GS, its not... so Nvidia updated drivers will not load (says "no compatible hardware found").

There is an easy workaround though. By adding the mobile GPU definitiion to the INF file in the driver installer, this will allow the installer to recognize the mobile GPU cards. Fortunately there is a a very active laptop gaming community that supports this need. Google for LaptopVideo2Go and you will find where people are making the release and beta drivers from Nvidia "mobile" friendly. I would assume this will also work for any Macbook Pro users as well.

If you want really solid support for gaming, it is important to keep the drivers fairly updated. Nvidia usually releases beta drivers every 2-3 weeks to better refine gaming compatibility, but as I said, they wont work without tweeking for mobile GPUs unfortunately.

Hope this helps!

 

[fredsarran]

I hate Windows

Hi,

Cheers for your time and reply.

I will not use Windows, that is why I have a Mac. I do admit that Windows on an iMac 2.8 is very quick and the games generally work very well.

I will do gaming under OS X, and I would love to push X-Plane 9 to the highest settings possible. Any comments on that ?

Cheers.

 

[Cave Man]

So on my WHITE 24" iMac it can only address 3.3GB of RAM, due to the limitations of the 32bit (READ: 4GB) memorary address available.

That's because your white iMac has Calistoga. My white iMac has Santa Rosa, thus can address 4 gigs (and probably 8 gigs).

 

[eXan]

That's because your white iMac has Calistoga. My white iMac has Santa Rosa, thus can address 4 gigs (and probably 8 gigs).

Santa Rosa has first appeared in the first-gen Alu iMacs...

 

[xparaparafreakx]

iMac Computers (April 2008)
The iMac computers introduced in April 2008, based on the Intel Core 2 Duo microprocessor, provide two RAM slots that accommodate 200-pin DDR2 SDRAM SO-DIMMs up to 1.25” in height. The SO-DIMMs must be DDR2-800 (PC2-6400) compliant and must be unbuffered, unregistered, 8-byte, nonparity, and non-ECC.

The 2.4 GHz 20-inch iMac ships with one 1 GB, 800 MHz, SDRAM SO-DIMMs installed. The 2.66 GHz 20-inch iMac and 24-inch iMac ship with 2 x 1 GB, 800 MHz, SDRAM SO-DIMMs installed, for a total of 2 GB. The largest capacity SO-DIMM supported is 2 GB, for a total maximum of 4 GB.

Memory configure-to-order options are: two 1 GB DIMMs for a total of 2 GB or two 2 GB DIMMs for a total of 4 GB.

The memory controller supports 1 GB and 2 GB SO-DIMMs; other configurations are untested. Because the memory in the two slots is configured as a contiguous array of memory, when both SO-DIMMs are the same size and type, the interleaving function is able to improve performance.

The iMac supports a CAS latency of 5 or 6.

The width of each 800 MHz memory channel is 64 bits.

The maximum number of devices per SO-DIMM is 16. See Table 3 for device and DIMM configurations.

There you go.

 

[SaSaSushi]

Santa Rosa has first appeared in the first-gen Alu iMacs...

Right, the mid-2007 iMac released in August, 2007 was the first with Santa Rosa and thus the first to support 4GB (at least).

There you go.

There you go, indeed. Larger configurations just have not been tested presumably due to the non-existence at the time of development of larger than 2GB DIMMs.

I'm sure larger DIMMs would probably work fine but agree with the rest that if you need more than 4GB you're probably better off with a Mac Pro.

 

[fredsarran]

I'm sure larger DIMMs would probably work fine but agree with the rest that if you need more than 4GB you're probably better off with a Mac Pro.

Ok, so where could I get 8GB for my iMac in the UK and online ?

It will still be cheaper than buying a Mac Pro.