New MacBooks and MacBook Pros Support Up to 6GB

[MacRumors]

ZDNet points out that memory sales company Ramjet has published on their website that the recently MacBook and MacBook Pros can support a maximum of 6GB of RAM. This configuration is possible with the use of one 2GB and one 4GB stick.

This finding is consistent with the experiences of previous MacBook Pro owners. 8GB of RAM has been shown to cause stability issues under Mac OS X when the additional RAM is accessed. For some reason 6GB appears to be the practical limit on the latest MacBook Pros, despite hardware support for 8GB.

Apple officially advertises that the new laptops can only support up to 4GB of RAM.

Article Link: New MacBooks and MacBook Pros Support Up to 6GB

[rvk27]

thats great news (for macbooks)
the more the better

[Stridder44]

So I was never clear on this, can the early 2008 MBPs "support" 8 GB of RAM as well (or rather, run on 6 GB but has the hardware for 8GB)?

[Eidorian]

So do we have a verifiable reason why 8 GB doesn't work? It is a switch OS X does when seeing the hardware model identifier or what?

Originally Posted by Stridder44

So I was never clear on this, can the early 2008 MBPs "support" 8 GB of RAM as well (or rather, run on 6 GB but has the hardware for 8GB)?

Santa Rosa based Mac laptops are limited to 6 GB as well. I haven't seen any tests done on the iMacs that I know of.

Originally Posted by Small White Car

Interesting. I wonder if Snow Leopard will bring the ability to run 8 GB.

Of course, I'm sure they'll keep advertising them as only taking 4 GB, to help sell the next generation of laptops that "officially" support 8 GB!

Oh well. I like these secret features for folks like us that pay attention.

Yet it works on the Mac Pro under Leopard today.

[Joe The Dragon]

Originally Posted by Eidorian

So do we have a verifiable reason why 8 GB doesn't work? It is a switch OS X does when seeing the hardware model identifier or what?

Santa Rosa based Mac laptops are limited to 6 GB as well. I haven't seen any tests done on the iMacs that I know of.

Yet it works on the Mac Pro under Leopard today.

The mac pro has 4 ram channels with a sever controller.

[fireloss]

Originally Posted by Eidorian

Yet it works on the Mac Pro under Leopard today.

The Mac OS X definitely tries to detect what kind of Mac you are installing it on. It does NOT matter what Mac Pro is able to use. That has nothing to do with the MacBook Pro.

[kuwan]

The loss of dual-channel support when going to 6 GB is not likely to cause a noticeable decrease in performance. Anandtech did some tests of 15 real-world applications on a Mac Pro testing Dual-channel vs. Quad-channel performance. Of those 15 applications only 2 saw a performance increase over 5% (Pages - 19% and iDVD - 13%). The average performance increase was only 3.2% and if we exclude those two apps the average drops to only 1.2%. You'll likely never notice any drop in performance and the increase in RAM capacity is likely to have a much larger effect on overall performance.

Now these tests were on the Mac Pro, not the new MacBooks so behavior may be different. Stay tuned to Bare Feats as they plan on doing memory performance tests on the new MacBook Pro to see if there is any significant performance loss when not running dual-channel. As for me, I'd much rather have the extra 2 GB than the imperceptible performance advantage of dual-channel memory.

[solipsism]

Originally Posted by Eidorian

So do we have a verifiable reason why 8 GB doesn't work?

Not verifiable, but if we look at the pre-Santa Rosa chipset, we see that while teh CPU was 64-bit, the chip could only address 32-bit of total memory for a total of 4GB. With the system needing about 750MB of address space, plus any discrete GPU needing some addressing you could install 4GB but could only use a 3GB maximum.

This may be similar in that Nvidia has only allowed for a total of 8GB of memory addressing at this time, which would then be limited to about 7GB of actual RAM. The issues with 2x4GB sticks not working seems to be an easy firmware fix, but I have doubts that you'd be able to actually use the full 8GB on the new Mac notebooks.

(speculation)

[billmister]

Originally Posted by Digital Skunk

No, you don't...

lol. I come accross people like you EVERY day at work. The "know it all". The once who argue that they don't want 8gig iphone.. they want 3GIG iphone. etc... It provides humor really.

You should not really Assume. It doesn't look good for your part at ALL. In any case, My point is made. I do know what i talk about because i come around products like these EVERY DAY, and come accross "AVERAGE" "SERIOUS USERS" "PRO USERS" "TEENS" and "KNOW IT ALLS" ::cough cough::

Anyway i'm sure it will not matter. It will probably be great if they offered 10 gigs of ram because i'm pretty sure some "average" users will be there to buy it for running word and powerpoint.

Anyway my 2cents. People are free to use there computers how every they feel like it. After all it's their money/hobby/job/or interest. Some people use 6 gigs and it's great that they do. Ram does speed up some process in a computer.

And some people barely use word and itunes but want the macbook pro with 4 gigs of ram (coming from a pc). which again is FINE. My point is, if you are beyone the average user you understant what ram does and it's purposs. If not, it just sound funny for people to say things like "YES!! i can install 8 gigs of ram on my computer" meanwhile they max out at 942mb.... Or "i can't wait to get the 500gig internal HD" when they have 200 gigs for 2 years now and only have 54gigs used.

Thanks for the response

[billmister]

ANyway i'm done posting for this thread. Peace

[Digital Skunk]

Originally Posted by billmister

lol. I come accross people like you EVERY day at work. The "know it all". The once who argue that they don't want 8gig iphone.. they want 3GIG iphone. etc... It provides humor really.

You should not really Assume. It doesn't look good for your part at ALL. In any case, My point is made. I do know what i talk about because i come around products like these EVERY DAY, and come accross "AVERAGE" "SERIOUS USERS" "PRO USERS" "TEENS" and "KNOW IT ALLS" ::cough cough::

Buddy, you have NO idea. Too bad you wouldn't believe me even if I told you.

[schneb]

I'm wondering if Snow Leopard will clear up the 8Gb stability issues.

[Small White Car]

Interesting. I wonder if Snow Leopard will bring the ability to run 8 GB.

Of course, I'm sure they'll keep advertising them as only taking 4 GB, to help sell the next generation of laptops that "officially" support 8 GB!

Oh well. I like these secret features for folks like us that pay attention.

[MagicWok]

I would also presume that by using 2gb+4gb you lose the dual data-architecture as you're no longer using matching pairs.

Does the extra memory negate this loss?


For those not knowing: http://en.wikipedia.org/wiki/Dual-channel_architecture

[Eidorian]

Originally Posted by MagicWok

I would also presume that by using 2gb+4gb you lose the dual data-architecture as you're no longer using matching pairs.

Does the extra memory negate this loss?

You're going to want more RAM vs. dual channel.

[ChrisA]

Originally Posted by MagicWok

I would also presume that by using 2gb+4gb you lose the dual data-architecture as you're no longer using matching pairs.

Does the extra memory negate this loss?

I think the extra RAM helps if you use it. Most would not realy put it to use if all they did was email and the web. But if you were a big user of VMware's Parallel or video editing with FCP or even Aperture. But for casual use it is hard to justify more then 4GB

As you point out the memory does technically run faster with 4Gb then with 6GB

[wizard]

What I would like to see is somebody with a 6GB MBP take the two DIMMS and swap slots the RAM is in. What I'm wondering is if Apple simply didn't implement an address line to one of the slots to prevent 8GB installations. If the 4GB DIMM only works in one slot then we have learned something more than we know today.

As for RAM upgrades I don't think I'd bother to go past 4GB right now. You really want to see how Snow Leopard clears things up. Because if the problem is software and not hardware it could be fixed in a newer release of Snow Leopard or lower level software.

Sadly I suspect that the RAM limit is an artificial reality that Apple built into the hardware.

Dave

[shen]

Originally Posted by ChrisA

I think the extra RAM helps if you use it. Most would not realy put it to use if all they did was email and the web. But if you were a big user of VMware's Parallel or video editing with FCP or even Aperture. But for casual use it is hard to justify more then 4GB

As you point out the memory does technically run faster with 4Gb then with 6GB

and with the new graphics chips providing a big part of the performance increase, does the RAM speed affect them?

i would want to see some very extensive benchmarks before i decided between 6 gigs and matched speed. the equation is getting too messy.....

[abrooks]

Originally Posted by MagicWok

I would also presume that by using 2gb+4gb you lose the dual data-architecture as you're no longer using matching pairs.

Does the extra memory negate this loss?


For those not knowing: http://en.wikipedia.org/wiki/Dual-channel_architecture

Meh, it's a toss up. Those wanting performance for 3D work etc. should probably stick too 4GB of RAM in matching pairs to get performance. But those looking purely for large amounts of RAM should go for 6GB.

[EagerDragon]

This is the 3rd or 4th thread basically dealing withthe same issue. I still do not understand why someone have not loaded a NIX 64 or a Vista 64 OS to check it with 8 Gig.

I did hear about OSX becoming unstabled with 8Gig, but I have yet to see anyone say what happens with NIX 64 or Vista 64.

By know you would think that someone had figured out if the issue was in OSX, the EFF, or hardware.

Several Mags have done extensive tests on other MacBooks but for some reason they have not done so with this new revision of MacBook and MacBook PRO.

I rather run 4 or 8 and not a hack.

Another possibility .... Maybe OSX maps some of the special addresses above the 6 Gig address space, as such adding memory above the 6 Gig threshold causes memory corruption because the OS is storing values there that should not be changed by running applications. Just a shot in the dark.

[rumplestiltskin]

If the new MacBook will accept (and, more importantly, use) 8GB of RAM under Snow Leopard, then that seals the deal AFAIC. I'll sell my white 2007 MacBook after Steve tells me that this is true.

Until I can have 8GB running properly under OSX in a MacBook, there's no compelling reason for me to make any changes.

By the way: The same goes for my iMac; let me use 8GB of RAM and I'll have a reason to upgrade.

(No, the MacPro is a behemoth and doesn't interest me in the slightest.)

[andiwm2003]

did i get this right: to old MBP's can also have 6GB of Ram?

This finding is consistent with the experiences of previous MacBook Pro owners.

[Eidorian]

Originally Posted by andiwm2003

did i get this right: to old MBP's can also have 6GB of Ram?

http://forums.macrumors.com/showthread.php?t=573906

[bilbo--baggins]

Could it be a heat issue? Have people investigated whether the stability issues are due to overheating? Maybe not, they tend just to auto-shutdown if they're getting too hot before they show signs of instability.

[MagicWok]

Originally Posted by bilbo--baggins

Could it be a heat issue? Have people investigated whether the stability issues are due to overheating? Maybe not, they tend just to auto-shutdown if they're getting too hot before they show signs of instability.

No, it's not to do with heat. Leopard is just unstable when 8GB is used in MBP's. It has been tested... Read the MR thread above.