4 GB RAM in MacBook Pro?

jne381

macrumors regular
Original poster
Feb 27, 2006
208
0
Grand Rapids
With Apple giving the ability to put 3GB of RAM in the new iMac, do you think it will bump up the RAM capacity in the MacBook Pro to reach 4GB?

Also why can't they put 4 GB of RAM in the new iMac? I believe it has 2 slots for memory, why does Apple only give the option of upgrading one to a 2 GB stick?
 

Foggy

macrumors 6502a
Jul 4, 2006
513
5
London, UK
I believe it is to do with some restriction in the 32 bit OS that can only address 4gb of memory in total (including video memory).

I could be totally wrong though.
 

LionsKiss

macrumors member
Sep 5, 2006
97
0
HK
From Wiki
I guess they want people to go with Mac Pro for the power hungry buyers?


http://en.wikipedia.org/wiki/64-bit
. A 32-bit register meant that 2[to the power of]32 addresses, or 4 gigabytes of RAM, could be referenced. At the time these architectures were devised, 4 gigabytes of memory was so far beyond the typical quantities available in installations that this was considered to be enough "headroom" for addressing. 4-gigabyte addresses were considered an appropriate size to work with for another important reason: 4 billion integers are enough to assign unique references to most physically countable things in applications like databases.

However, with the march of time and the continual reductions in the cost of memory (see Moore's Law), by the early 1990s installations with quantities of RAM approaching 4 gigabytes began to appear, and the use of virtual memory spaces exceeding the 4-gigabyte ceiling became desirable for handling certain types of problems. In response, a number of companies began releasing new families of chips with 64-bit architectures, initially for supercomputers and high-end workstation and server machines. 64-bit computing has gradually drifted down to the personal computer desktop, with Apple Computer's Mac Pro desktop line (as well as the Power Mac G5 before it) using a 64-bit processor (for the Mac Pro, the Intel Xeon), and AMD's "AMD64" architecture (implemented by Intel as "EM64T") becoming common in high-end PCs. The emergence of the 64-bit architecture effectively increases the memory ceiling to 2[to the power of]64 addresses, equivalent to 17,179,869,184 gigabytes or 16 exabytes of RAM
 

robbieduncan

Moderator emeritus
Jul 24, 2002
24,638
61
Harrogate
A 32-bit machine can support more than 2Gb or RAM (the total memory space is 4Gb, but some of this is need to memory map peripherals and so on, normally 3Gb of RAM should be possible). On the MBP there is some restriction in the hardware, or possibly the firmware that limits it to 2Gb. People have tried using 2Gb SO-DIMMS. Using a single one is fine, 2 does not work (does not even try and boot the OS). One 2Gb + one 1Gb also does not work.
 

ZoomZoomZoom

macrumors 6502a
May 2, 2005
767
0
jne381 said:
With Apple giving the ability to put 3GB of RAM in the new iMac, do you think it will bump up the RAM capacity in the MacBook Pro to reach 4GB?

Also why can't they put 4 GB of RAM in the new iMac? I believe it has 2 slots for memory, why does Apple only give the option of upgrading one to a 2 GB stick?
Maybe they don't have enough 2GB sticks of 'Apple RAM'? I have no clue though.
 

BackInTheSaddle

macrumors regular
Aug 20, 2002
118
0
Olympic Peninsula, WA
Somewhere I read that the 2GB limit is the result of an issue with Intel's EFI (or perhaps, Apple's implementation of Intel's EFI). Does anyone know definitively why the MB and MBP cannot support more than 2GB?

I would really love a laptop that could have 4GB of RAM...would really mitigate some of the resource constraints when running any apps with Rosetta.
 

generik

macrumors 601
Aug 5, 2005
4,116
1
Minitrue
Could it be fixed in a laptop firmware update? Or could Apple be using the old version of Napa chipset for the new Core 2 chips?
 

mikesk8

macrumors member
May 17, 2006
86
0
Helsinki
ZoomZoomZoom said:
Maybe they don't have enough 2GB sticks of 'Apple RAM'? I have no clue though.
For iMac its a natural limitation - iMac = consumer product. If you want to have more you are forced to buy Mac Pro. Laptops its a different story..Pro ones are not so Pro; maybe because they didnt have time in Jan to make them better:p
 

Abstract

macrumors Penryn
Dec 27, 2002
24,415
124
Location Location Location
I think Apple is just being morons, but if there's a logical explanation as to why, then I'll take that back. However, it's not the first time they have crippled their own machines. I just have some doubts that they'd cripple their MacBook Pro.
 

jamesborr

macrumors newbie
Sep 21, 2006
1
0
Proper support for 4GB requires...

Folks,

3 things are needed for proper support of 4GB of memory on a laptop:

  • 64 bit capable OS (good to go)
  • 64 bit capable CPU (good to go with Merom)
  • >32 (usually 36) bit Chipset (who knows when)
The problem is that there are a whole series of devices, requirements, etc. for memory below 4GB. These elements typically add up to approximately 1GB, and thus mask or hide everything above approximately 3GB of memory. Thus, even if Apple removes the currently limit of 2GB, they are powerless to make more then 3GB of memory available at the OS level, even when they upgrade the CPU to Merom. Intel's latest greatest mobile chipset (maybe this will change sometime next year) is only a 32 bit chipset (I guess they think it is still 1999). With a 1000% premium on 2GB SO-DIMM's (versus 1GB), it's a little annoying to have half of the second stick go to waste.