New MacBook Pro Does Not Support 8GB RAM (for now)

[MacRumors]

Luke from iFixit.com was kind enough to test out a new NVIDIA-based MacBook Pro with 8GB of RAM (two 4GB chips) to see if the earlier reports were true. NVIDIA representatives had stated that the new chipsets used in the MacBook and MacBook Pro could support up to 8GB of RAM. Previous generation MacBook Pros could only reliably support up to 4GB of memory.

Preliminary results show that while the new MacBook Pro did recognize the entire 8GB of RAM, during actual usage, the computer appeared to be limited to 4GB:




The machine would hit an invisible wall at 4GB and act like it had run out of memory. It's unclear why this limitation exists, as Mac OS X is able to use more than 4GB on Apple's Mac Pro. As a result, MacBook and MacBook Pro owners should not expect to be able to upgrade to 8GB of RAM at this time.

iFixit has posted a disassembly guide for the new MacBook Pros including RAM replacement and will post updates about these results after further testing.


Article Link: New MacBook Pro Does Not Support 8GB RAM (for now)

[mayanka89]

Maybe the Mac Pro build is different?

[pismodude2]

Noooooo!!! Oh, well. Snow Leopard to the rescue!!!

[illegallydead]

interesting. I'm pretty sure that leopard is leopard is leopard, no matter what kind of machine you have, so I'm not sure why this would be a limitation. Very odd that this is happening. With leopard being a "64-bit" OS, why would they ever limit the memory it could access? What possible benefit could this have to write this code blocking more than 4Gb into the OS?

Ideas anyone?

[jasonrm]

Disapointing at the moment, but I am hopeful that in time this limit will be removed. Untill then 4GB is good for what I need, but I completely understand why some folks might need more.

It should be said again, Apple never promised that 8GB was supported, so no one is being cheated here, despite the complaining that always follows bad news...

Originally Posted by mayanka89

Maybe the Mac Pro build is different?

Yes. Apple chose to fully support up to 32GB of ram from early on, which is a respectable max for a desktop and in my opinion, 4GB is a decent max on a laptop. I'm looking forward to the possibility of 8GB, but I bought the new MBP knowing that 4GB might always be the limit.

[dizastor]

Originally Posted by pismodude2

Noooooo!!! Oh, well. Snow Leopard to the rescue!!!

Unfortunately, I think all of these little tidbits are building to become the 'value' in snow leopard.

The dual video cards, the max ram... possible only available if you shell out $129 for snow leopard.

[trule]

Could it be a limitation of the CPU?

[flashEX]

Try booting a Ubuntu or any latest Linux Live CD and run the command "free" when it successfully boots? Best way to see if it's hardware is capable of 8GB

[jasonrm]

Originally Posted by trule

Could it be a limitation of the CPU?

As best as I can tell, it's not a chipset nor a CPU limit, rather either EFI or OS limit.

Has anyone installed a 64-bit Linux on a new MacBook Pro with 8GB?

[GekkePrutser]

Probably an EFI limitation as the chipset seems to recognize the memory fine. I'd say it could be fixed with a firmware update. But I wouldn't put it past Apple to leave this for later models only and tout it as a new feature

[ChrisA]

What if you boot Linux? Is the 4GB limit in Mac OS X or is it in the hardware? If you have a Linux boot CD around you could find out in 10 minutes.

[SailorTom]

Originally Posted by flashEX

Try booting a Ubuntu or any latest Linux Live CD and run the command "free" when it successfully boots? Best way to see if it's hardware is capable of 8GB

?
can you explain a bit more pls

also how does tht help in OS X?

[Brien]

Originally Posted by GekkePrutser

Probably an EFI limitation as the chipset seems to recognize the memory fine. I'd say it could be fixed with a firmware update. But I wouldn't put it past Apple to leave this for later models only and tout it as a new feature

Exactly, I wouldn't be surprised if they did this just to upsell the new models later on.

[GekkePrutser]

Originally Posted by Brien

Exactly, I wouldn't be surprised if they did this just to upsell the new models later on.

Yeah especially since they did exactly the same with my old PowerBook G4 1.33. The new model had two-finger scrolling and safe sleep, both of which the hardware on mine supported too. Both features worked totally fine with third-party tools (iScroll2 and iHibernate if I recall correctly).

Of course, in this case it's much harder for anyone to write a third-party way of solving this, a firmware is not nearly as easily modified as a simple device driver.

[Sbrocket]

Originally Posted by SailorTom

?
can you explain a bit more pls

also how does tht help in OS X?

It doesn't, but it demonstrates that the hardware is capable of supporting 8GB of RAM and that the 4GB limitation is enforced in software at some level.

[theheyes]

Originally Posted by SailorTom

?
can you explain a bit more pls

also how does tht help in OS X?

It doesn't help, but you can rule out the Operating System if Linux runs into the same wall.

[MichaelLatta]

If Linux can see and use 8GB then apple can release a software update that makes the 8GB accessible. If Linux can not see it there may be some hardware (address line) limit that has nothing to do with the chips but has to do with the motherboard design. So if it is only software then Apple can fix it for the existing models.

Given there are Dell laptops with 8GB I presume it is not the CPU. I would guess that the XEON driver allows addressing more RAM and the Core2Duo driver does not. This can be fixed with a software update, but might have to wait for Snow Leopard when making use of the RAM will be easier. With Leopard unless the app is 64bit no ram above 4GB can be used. With Snow Leopard the OS gets relocated so that this is not an issue. With the Mac Pro you can not get all the RAM contiguous as the OS takes a chunk at the 4GB boundary for itself.

[shigeya]

On my MBP, sum of Free+Wired+Active+Inactive =~ Used.

This graph showing different number. And the green, free area is at 3.83G.
And the wired and active region is outside of the "free" 3.8GB area.

So, it's not limited to 4G. But it is not fully make use of 8G (looks like).

[minijon]

I'd say its in the EFI -- The Mac Pro's support it, and its the same Leopard (Otherwise there would be a patch/hack to enable it.) Wouldn't a limitation at that level also effect what any other operating system could see as well?

[flashEX]

Originally Posted by shigeya

On my MBP, sum of Free+Wired+Active+Inactive =~ Used.

This graph showing different number. And the green, free area is at 3.83G.
And the wired and active region is outside of the "free" 3.8GB area.

So, it's not limited to 4G. But it is not fully make use of 8G (looks like).

You might want to make sure also you are using a 64-bit Linux distro. Because that guarantees you are going to see the full 4GB or 8GB if you have that much.

[kironin]

Originally Posted by dizastor

Unfortunately, I think all of these little tidbits are building to become the 'value' in snow leopard.

The dual video cards, the max ram... possible only available if you shell out $129 for snow leopard.

Ah, one more reason to remain with Tiger and skip over Leopard to Snow Leopard!

[Rocketman]

This is a case where Steve should write one of those short notes saying if this is a hard limit or if a future firmware or software update "may" address this. This product is a long way from EOL (200 days average) and in about 4 months, 8gb of memory will be quite affordable. The product itself has about a 5 year lifespan.

Rocketman

[insideo]

Originally Posted by shigeya

On my MBP, sum of Free+Wired+Active+Inactive =~ Used.

This graph showing different number. And the green, free area is at 3.83G.
And the wired and active region is outside of the "free" 3.8GB area.

So, it's not limited to 4G. But it is not fully make use of 8G (looks like).

Based on the image shown, the article is completely wrong. The OS is clearly seeing 8 GB, but the load on the system is such that only about 1/2 that is currently being used. Until swap goes > 0, this is simply a matter of not throwing enough at the system to get it to work hard. The fact that used and free are both approximately 4 GB is completely coincidental.

[Loge]

Since the older MBPs worked with 6GB according to the various threads on this forum, so this does appear to be a step backwards.

[bakedalaska]

8GB of RAM is desirable - cause bigger is better and after all if DELL can do it with the same chips... Also if you are trying to run Windows as well as OS X you need all the memory you can get.

Reading this post - did anyone actually try the Linux boot thing and prove it one way or the other?

Anyone: Does Mac Fusion see the extra memory?

I agree too that it would be in Apple's interests to issue a statement about this.

Incidently how does one email apple on an issue like this?! Can one...

I know they are not going to answer but perhaps if enough people asked...