MB: supported memory

[FinneousPJ]

Hello,

what is the limiting factor on memory support? I thought modern CPUs had the memory controller on chip. My logic would thus dictate the CPU determines the amount of RAM usable by the system, not the MB. Why do motherboards list the supported memory? Why does one e.g. socket LGA1366 MB support 24 GBs and another 48 GBs?

Thanks,
FinneousPJ

 

[borisof007]

It's the number of available memory slots.

Take these two examples:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813188069
This motherboard only supports (I say "only", heh) 24 gb's because it has 6 memory slots.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813188070
This motherboard supports 48 gbs because it has 12 memory slots.

 

[IntelEnthusiast]

There is a little bit more to it then that. The Intel® Core™ i7-980 only supports up to 24GB you can see the maximum memory supported at http://ark.intel.com/products/58664/Intel-Core-i7-980-Processor-(12M-Cache-3_33-GHz-4_8-GTs-Intel-QPI) . The Intel Xeon® X5690 which is supported on the second board can reach over 288GB. Which you can see at http://ark.intel.com/products/52576/Intel-Xeon-Processor-X5690-(12M-Cache-3_46-GHz-6_40-GTs-Intel-QPI) .

In the end it is both the board and the processor that set the maximum supported memory.

Christian Wood
Intel Enthusiast Team

 

[FinneousPJ]

@boris

No, I've seen some boards list supported memory as 6*4 = 24 while others have 6 * 8 = 48 - obviously 8 GB sticks are ridiculously expensive at the moment, I'm just curious why.

@Christian

I see. Can you shed some light on as to what is the limiting factor? The Xeon has a more advanced memory controller I guess..?