Can Snow Leopard handle 8GB in a MBP from 2007?

Hello-

I remember a few months back I was going to do the 6GB RAM upgrade, since it was established that my generation MBP (late 2007) could handle 4GB DIMM + 2GB DIMM = 6GB total. Articles I saw at the time said 8GB wasn't possible because OS X couldn't handle it. I was wondering if Snow Leopard can? Anyone with access to 2x 4GB DIMMs want to give it a try?

Thanks!

-TM

It is not an OS X issue. OS X has been quite capable of handling more RAM for some time. It is a hardware limitation. My late '06 is limited to 3GB useable.

If it was an OS X limitation, the newer MacBook Pros would still not be able to handle up to 8GB nor would the Mac Pro be able to handle up to 32GB in Leopard.

bobtomay, I'm not undermining you, but I was basing it off of this story from Gizmodo last year: Confirmed: New MacBooks Support 6GB RAM - macbooks maximum RAM - Gizmodo Lots of people followed up indicating the OS was holding it back. I will admit I haven't read all the comments though.

Here's an excerpt from the main article:

"According to the rep I spoke to, Ramjet's tests and previous experiences by others have shown that 8GB of RAM in a notebook throws OS X into fits, making it unstable for actual use. Ramjet claims though that 6GB is a screamer—utilizing a fresh new 4GB 1066 SO-DIMM paired with a 2GB; the performance gained by having an extra two gigs negates the performance loss that tends to follow from having an unmatched pair of differently sized modules. [...] But it's possible.

So when's that update for true working 8GB support on these notebooks going to come, Apple?"

If it was only a hardware issue, OS X wouldn't be "thrown into fits", it simply wouldn't boot at all, right?

I'll stand by what I've posted until someone proves me wrong.

See my below post

Hard limit and soft limit

Hey, I had the same question to and did some research. So heres what I found:

1- "The MAC OS has always been supporting 64-bit, but Snow Leopard takes a big step...". This extraction from the Apple's Snow Leopard ad means that handling 8Gb is NOT a problem in prev OSes. In other word, I think its not a software limit.

2- So the other kind of limit is hardware. Im kind of a stranger in this realm but Im sure the limit has something to do with a MB(P)'s chipset. A lookup in Wikipedia's "List of Intel mobile chipsets" seemed to confirm my belief: each processor (in my case, Core 2 Duo) has to go with certain chipset models. I dont know what a chipset is, but The important point is that each chipset supports different kinds of RAM (DDR2, DDR3), at different speeds (667, 1066, 1333 MHz) and up to a maxium amount (4BG, 8GB).

In short, I think we can find out the hard limit of memory support by matching our laptop specs with those mobile chipsets on the list.

Maybe somebody more familiar with hardware can give us a head up on this matter.

Matrix said:

Hello-
I was wondering if Snow Leopard can? Anyone with access to 2x 4GB DIMMs want to give it a try?

Thanks!

-TM

Click to expand...

Yes...this is the key parameter...those 4 gig sticks of ram. They are pretty darn pricey...and two of them even worse.;D

- Nick

The amount of memory supported by your iMac or MacBook (Pro) depends on its chipset. It's the same for a PC. Plain and simple - Snow Leopard although a 64 Bit OS which can support massive amounts of memory, will still be limited by the current chipset used in the machine.

I'm not even sure that a firmware update would be able to change that. BTW, if you wish to confirm what I and the other poster said, just go to the Intel web site and look up the spec sheet for your CPU and chipset.

Regards.

chscag said:

The amount of memory supported by your iMac or MacBook (Pro) depends on its chipset. It's the same for a PC. Plain and simple - Snow Leopard although a 64 Bit OS which can support massive amounts of memory, will still be limited by the current chipset used in the machine.

I'm not even sure that a firmware update would be able to change that. BTW, if you wish to confirm what I and the other poster said, just go to the Intel web site and look up the spec sheet for your CPU and chipset.

Click to expand...

I agree. The amount of RAM a machine can handle is both limited by hardware and software. When Apple states that "64-bit computing shatters that barrier by enabling applications to address a theoretical 16 billion gigabytes of memory, or 16 exabytes", they are referring to the software potential. This is why they say theoretical because there is still hardware limits. It will be a while still before hardware can come close to handling that much RAM. On top of this, 98% of computer users don't need more than 4GB which is still more than most people need.

bobtomay said:

It is not an OS X issue. OS X has been quite capable of handling more RAM for some time. It is a hardware limitation. My late '06 is limited to 3GB useable.

If it was an OS X limitation, the newer MacBook Pros would still not be able to handle up to 8GB nor would the Mac Pro be able to handle up to 32GB in Leopard.

Click to expand...

listen to this person , hardware limitation first then software,. someone also mentioned chipset, if you came from the pc world you would know more about it (maybe), i can add 10gb ram to my pc but windows wont utilize over 3gb (i think), the MB will see it, love it, but the OS will just snobb at it;D ..

For anybody interested in how Mac OS X handles memory verses 32 bit windows here is a good article

Road to Mac OS X Snow Leopard: 64-bits, Santa Rosa, and the great PC swindle — RoughlyDrafted Magazine

Thanks for all the replies. Louishen's link was tremendously enlightening and I recommend anyone interested in the differences between 32/64-bit read it.

I have spent hours researching this, and learned a few things. First, the term "Santa Rosa" is the description given to the 4th generation Intel Centrino platform released in May 2007. This platform must consist of three things: a chipset (Crestline), a processor (Core 2 Duo), AND an Intel wireless network adapter (Kedron). As a set, and only as a set, this was codenamed "Santa Rosa." However, Apple chose to drop the Intel network adapter and replaced it with another manufacturer's (Broadcom I believe), making the term "Santa Rosa" no longer relevant in this instance. Meaning, it is only correct to say "a mid-2007 MBP uses an Intel Crestline chipset".

When you look up that chipset, you see the following specifications:

Chipset: PM965
Codename: Crestline
Part Numbers: 82965PM (MCH)
South Bridge: ICH8-M
Release Date: May 2007
Processor(s): Core 2 Duo
FSB: 533/800 MHz
Memory: DDR2 533/667
Max Memory: 4 GB
Graphics: PCI-Express 16x
Power: 8W

This clearly states the maximum actual memory is 4GB, as confirmed by Apple, by various Wikipedia articles and by Intel themselves at http://www.intel.com/Assets/PDF/datasheet/316273.pdf.

So that seems like it should clear things up, right? Wrong. Because there are plenty of confirmed reports that some MacBook Pro's can handle 6GB, completely defying the specifications set forth by the manufacturer. This site, Understanding Intel Mac RAM - Mac Guides has quite a bit of good information, here's an excerpt:


A bit more research yields this thread 6GB in MacBook (Pro); Yes it works. - 8GB... well... - Mac Forums which acknowledges MBP (mid-2007) users cannot add two 4GB modules because "Accessing memory above 4GB seems to cause OSX to throw the extras into swap, making the rest of the 4GB physical memory useless." They also go on to state "Currently, OSX Leopard (10.5.x) seems to have trouble accessing above 6GB of physical ram. Further testing is being done, but currently, 6GB is the max that is considered 'safe'."

So why can a chipset with a confirmed maximum memory of 4GB, still reliably and comfortably support 6GB? That fact completely undermines anyone using whitepaper specifications as an argument against 8GB as it proves the specs are apparently inaccurate. And the fact that 8GB of RAM successfully boots, and successfully shows 8GB installed but then causes the OS's memory management to choke certainly points to an OS issue to me.

However, I recognize that even if it is an OS issue, it's important to note that there is no reason to assume Snow Leopard is any kind of magic pill that will magically fix whatever the OS is choking on when using 8GB of memory.

They could update the firmware if they chose to. It's not that difficult, IBM does RAM and CPU processor cores enablement as a paid upgrade as a matter of course. Apple did it with wireless n a while back.