memory configs on x58 vs p55

[biostud]

I know that you have to fill up three slots on the x58 and two on the p55 to get full bandwidth, but do you have to use same size of memory blocks?

couldn't you do at 2+4Gb (or 2x2+2) on a p55 to get 6gb or 4+2+2 (or 2x2+2+2) to get 8gb on the x58 and still get same stability/bandwidth?

 

[n7]

Ideally you'd want 3 or 6 DIMMs for X58 to maintain full bandwidth triple channel, & 2 or 4 DIMMs for P55.

You can use mismatched size DIMMs if you really wanted.

In reality, the difference is minor at best, & is not really discernable in anything but synthetic benchmarks.

I run 4x2 GB on my X58 & it does quite nicely

 

[biostud]

but even with you config it says triple channel

 

[n7]

but even with you config it says triple channel

It is triple channel via Flex Mode.
The fourth DIMM is basically in single channel if i understand it correctly.

Contrary to what people like to [falsely] claim, the performance "loss" is extremely minimal.

 

[biostud]

So there's no reason to make the decision to buy either of these platforms based solely on the amount of memory you want installed, unless you need really large amounts of memory.