03-13-2008, 05:15 PM

im about to get the mbp coreduo and i really want to push it beyond the 2gb ram limit if i can. i plan on using extensive 3d cad software on the windows side and also push it with aperture and final cut on the mac side. im afraid 2gb ram wont be able to let me run everything smoothly. here is the only information i found containing any type of technical explanation about it. i got it from the macrumors forum. i just wanted maybe a better and more complete explanation on this ram limit. some people say they have the same chip architecture as the c2d's but yet different limits. i was just wondering if anyone has tried putting in 4gbs of ram and actually running benchmarks on it eventhough the mbp still says 2gb readable and if it makes it any faster. and if it does, will it overload the chip in the long run and ruin something? i went thru 5 pages of searches and google the crap out of it and the below information is only thing i've found with some decent explanation on the ram limit.


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"The latest model MacBook Pro has the new Intel Santa Rosa chipset, which
supports more than 3 GB of RAM. Apple says it supports 4 GB. I haven't
checked what Intel says, but it might be possible to go higher than 4 GB
if larger memory becomes available in the same package in future. I
doubt it - this is more likely to be an option in the next upgrade.

The second generation (Core 2 Duo) has an older chipset which supports 3
GB of RAM. The Core 2 Duo CPU can address more than 4 GB of total
address space, but the chipset imposes a limit by only supporting a
32-bit address space (4 GB). 1 GB of the address space is reserved for
PCI Express peripherals, firmware, and video card memory, leaving 3 GB
for RAM.

The first generation (Core Duo) probably has the same chipset as the
Core 2 Duo model but there may be an additional artificial limit which
stops you from getting that third gig of RAM. For example, it may have a
different organisation of its address space, or only physically have
enough pins going to the RAM slots to address 1 GB per slot."

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03-13-2008, 06:44 PM

There's some articles in this link you can check out. It seems some have tried, but "readers who managed to get an early shipment of a 2GB RAM stick were disappointed to find that their MacBook "blackscreened" when they installed the RAM."
http://www.everymac.com/systems/appl...-capacity.html

03-14-2008, 12:00 AM

thanks i've read that one. but it just says that they dont work and nothing else about why it didnt work. blackscreened huh. hmm.

03-14-2008, 12:12 AM

I'm running 4GB on a SR MBP and haven't had any problems. Of course it says 4GB of RAM is supported so that's what you would expect.

03-14-2008, 01:51 AM

well is ur mbp a core duo or c2d? im specifically asking about the core duo since the limit on the 1st gen mbp is 2gb and 2nd gen mbp is 3gb and after newer is 4gb. if u have a coreduo does your info actually say 4gb or just 2gb?

03-14-2008, 09:59 AM

as far as i know all the macbook pros with merom have 4GB compatibility...& apple even provides users with a choice to upgrade 2 4GB RAM while ordering the MBP (though it would be cheaper to buy it elsewhere)

are you planning on buying a second hand/refurbed computer? core duo isn't available on any of the models in stock now...all have core 2 duo penryn processors as of last month...

03-14-2008, 11:09 AM

yes i am planning to purchase my friends first gen mbp with these specs. 2.0ghz 100gb 256mb vram. right now theres only 1gb stick in there. i really wanna push past the 2gb limit on it.

03-14-2008, 11:39 AM

The new C2D MBPs, well all C2D chips are 64 bit so they can physically work with more RAM. Core Duo processors are 32 bit so they will only recognize the maximum of 2GB.

03-14-2008, 12:22 PM

Originally Posted by bryphotoguy

The new C2D MBPs, well all C2D chips are 64 bit so they can physically work with more RAM. Core Duo processors are 32 bit so they will only recognize the maximum of 2GB.

Woah there - 32-bit computers can address 4 gigs of memory, although some of this is lost to hardware addressing such as the GPU, memory controllers etc. But there is no technical reason why a 32-bit CPU cannot use at least 3 gigs, and sometimes more.

Additionally, memory addressing has NOTHING at all to do with physical RAM, it's ALL memory addressing, including virtual space.

The 2 Gig RAM limit on the original Core Duos is either entirely artificial and was done for marketing reasons, or down to the Mainboard design. There are plenty of 32-bit PCs running windows with 4 gigs of RAM (even though Windows can only usually use about 2.8 gigs typically).

More here

http://www.anandtech.com/gadgets/showdoc.aspx?i=3034

http://www.anandtech.com/cpuchipsets...oc.aspx?i=3044

03-14-2008, 12:42 PM

Sorry, I didn't know that. That's what I was told.
maybe it's software based?
What Mac running OS X in 32 bit is capable of running or addressing more than 2GB of RAM? I realize you said Windows can run 2.8GB but I wonder if it's a software issue?
I wouldn't put it past Apple to artificially put the 2GB limit to boost sales. Core Duo processors aren't much slower than the new 45nm Core 2Duo processors. If the original MBP supported 4GB RAM, there wouldn't be much to upgrade to.

03-14-2008, 01:31 PM

Originally Posted by bryphotoguy

Sorry, I didn't know that. That's what I was told.
maybe it's software based?
What Mac running OS X in 32 bit is capable of running or addressing more than 2GB of RAM? I realize you said Windows can run 2.8GB but I wonder if it's a software issue?
I wouldn't put it past Apple to artificially put the 2GB limit to boost sales. Core Duo processors aren't much slower than the new 45nm Core 2Duo processors. If the original MBP supported 4GB RAM, there wouldn't be much to upgrade to.

I think it's a marketing thing, although there are some reasons why you'd want to limit it to 2 gigs, because dual channel RAM (1+1 gig, or 2+2 gig) works better than mixed RAM (1+2gigs).

A single application (including the kernel) cannot address 4 gigs of RAM in one go on a 32-bit system because of the reasons stated in the article. Many 32-bit Windows machines shipped with 4 gigs of RAM, but Windows always showed 2.5 gigs or occasionally 3 gigs. Microsoft's answer, Windows will now show the installed RAM, not the useable RAM - so Windows will simply lie - nice patch MS!

I'd imagine that OS X is more sophisticated than Windows when it comes to memory management, because it does not carry the legacy x086 code needed for addressing more than 640k from the very old days (where this comes from). Having said that, Apple may simply have decided to simplify everything and restrict the lower end machines to 2 gigs, to prevent this controversy ever coming up.

For the record, a 32-bit OS and CPU can address a maximum of 4 gigs of memory (not necessarily RAM), meaning in practice, around 2.5 - 3 gigs could be available to the user.

03-14-2008, 04:53 PM

so really the first gen mbp can at least access 2.5 to 3gbs of ram. but somehow apple is limiting it? i wonder if there is a workaround for this. i wish there is someone out there that has tried testing this theory on the first gen mbps. here's a scenario, benchmark 2 first gen mbps, one with 2 1gbs sticks (total 2gbs), and one with 2 2gbs sticks (total 4gbs) and see if there is any performance difference between the two. also wasn't the 2nd gen mbps 32bit but also core2duos? because i know that they were able to show only 3gbs of ram when 4gbs were put in it.

03-14-2008, 05:06 PM

Originally Posted by sdsviet

well is ur mbp a core duo or c2d? im specifically asking about the core duo since the limit on the 1st gen mbp is 2gb and 2nd gen mbp is 3gb and after newer is 4gb. if u have a coreduo does your info actually say 4gb or just 2gb?

It's a C2D.

03-16-2008, 01:54 AM

so it looks like no one out there has actually tried benchmarking the rams? i would but as of right now i dont have the laptop yet and i dont too much about actually doing the benchmarking. tried it once, didnt work too well. haha

03-16-2008, 02:58 AM

As far as the technical specifications are concerned (without reading into the meaning behind them):

MacBook Pro CD: 2 GB RAM Max

MacBook Pro C2D (Models through late 2006 Revision): 3 GB RAM Max

MacBook Pro C2D (Models with Santa Rosa Chipset): 4 GB RAM Max