6Gb RAM Limit in Early 2008 MacBook Pros with Snow Leopard OS

[AmazingRobie]

Hello. Does anyone know if the 6Gb limit will be able to be surpassed in early 2008 MacBook Pros when using the upcoming 64-bit Snow Leopard OS? And I mean actually be able to utilize all of the RAM not just have it be recognized. Let me know if anyone knows for sure. Thanks.

 

[robbieduncan]

What are you doing currently that can't utilise all 6Gb? What apps are you running, how are you measuring this usage etc. My understanding was that you could currently use 6Gb.

 

[AmazingRobie]

What are you doing currently that can't utilise all 6Gb? What apps are you running, how are you measuring this usage etc. My understanding was that you could currently use 6Gb.

I currently have 4Gb in my laptop ( I think it's considered a version 4,1, or something like that ), I've read several places that 6Gb is the unofficial limit. I'm a heavy Adobe Graphics Suite user, but I also run multiple applications in the background including video, audio, peer-to-peer applications, and I transfer large amounts of data to external devices pretty regularly along with some video editing from time to time. I'm not saying that the bump up to 6Gb wouldn't be more than sufficient, but I'm holding out on upgrading memory because I'd rather go to 8 than 6 if it will work.

 

[aaquib]

I believe the 6GB limit is a hardware limitation, not software; in which case Snow Leopard won't change the RAM limit.

 

[Hellhammer]

All RAM limits are hardware limits. Leopard is already 64-bit but 10.6 will be fully 64-bit. 10.6 has theoretical 16 terabyte (16 000Gb) RAM limit but you Mac's memory controller can't utilize more than 8Gb (Apple has set the limit to 6Gb I think)

 

[AmazingRobie]

I believe the 6GB limit is a hardware limitation, not software; in which case Snow Leopard won't change the RAM limit.

Does anyone know for sure that it's a hardware limitation; as I've heard both. I'll probably end up testing once I install Snow Leopard anyway, but if anyone has any technical knowledge and could confirm, it would be appreciated. Thanks for your input.

 

[Hellhammer]

Does anyone know for sure that it's a hardware limitation; as I've heard both. I'll probably end up testing once I install Snow Leopard anyway, but if anyone has any technical knowledge and could confirm, it would be appreciated. Thanks for your input.

It is, because why Mac Pro can take up to 32Gb and it's running the same 10.5 as you are. Read my post above

 

[AmazingRobie]

It is, because why Mac Pro can take up to 32Gb and it's running the same 10.5 as you are. Read my post above

Okay, I hear what you're saying, but Apple has officially set the limit to 4Gb, but there have been people who have successfully installed and used 6Gb without it crashing and then there have been those who have reported to have successfully installed 8Gb and had it register in the hardware profiler as 8Gb, but it doesn't utilize the full 8Gb and from my understanding it's unstable. So where does that leave it?

 

[Hellhammer]

Okay, I hear what you're saying, but Apple has officially set the limit to 4Gb, but there have been people who have successfully installed and used 6Gb without it crashing and then there have been those who have reported to have successfully installed 8Gb and had it register in the hardware profiler as 8Gb, but it doesn't utilize the full 8Gb and from my understanding it's unstable. So where does that leave it?

I'm not an expert on this (waiting for Eidorian to fix all this mess ) but your Mac officially supports 4Gb and that is what Apple offers but unofficially it supports 6Gb. Your memory controller should (not sure) support 8Gb but Apple has lowered the limit to 6Gb.

This is quite same thing as previous gen iMacs had, it can take 4Gb officially and 6Gb unofficially, still some people can't get 6Gb to work, so I think it depends on who is the manufacturer of the RAM.

Please someone correct me if I'm talking s**t here!

 

[jdechko]

I will do my best.

As far as I know, the memory controllers, either through nVidia or Intel can only address up to 6GB of RAM in that chipset. There are no 3GB sticks of RAM, so each RAM slot has to be able to correctly identify a 4GB stick of RAM, which is why 8GB is recognized but cannot be addressed/used. The MacPro's use a different chipset, which allow far greater than 8GB to be used, theoretically, they're only limited by the number of slots they have and the maximum available per stick/slot.

Hellhammer is correct, though, that it is a hardware limitation and not a software one. Logically speaking, why else could some machines that are running Leopard be able to use more than 8GB and some not?

 

[Azrel]

No, this particular MacBook Pro has no chance of running 8GB RAM. The chipset simply cannot address that much. (which is nothing to do with DIMM size which the above poster mentions).

It was only until the nVidia chipset (read 9400m graphic chip et all) MacBook Pros with the Unibody that could (theoretically) address 8GB. And only certain 15" MacBooks in the late 2008 models that could actually do this. Now all MBP's can address 8GB.

For your particular MacBook Pro it's a Hardware limit

As for my MacBook (late 2008) it's actually a firmware limit.

 

[fpar]

Deleted - I was talking crap.

 

[jdechko]

The chipset simply cannot address that much. (which is nothing to do with DIMM size which the above poster mentions).

I'm a little confused by your wording here. I did say that the chipset could only address 6GB but that the only conceivable way to do that would be a 4+2 or a 2+4 configuration. Are you agreeing with what I said?

 

[AmazingRobie]

Okay, thanks for all of your answers. After reading through them and then researching further on a couple of the RAM seller sites I have realized that there is no chance of going to 8Gb with my current machine. So has anyone here that's upgraded to 6Gb with an early 2008 machine (non-unibody MacBook Pro4,1) and uses Adobe Photoshop/Illustrator and perform video editing noticed a difference; all of the posts I've seen say that the boost is negligible because of the lack of dual channel performance due to mismatched RAM, so I'm probably going to see if the next iteration of MacBook Pros contain any significant increases in specs (i.e. Dual Layer BluRay recordable drive, more powerful processor, etc.) and give my current machine to my significant other. Thanks.