Mac Pro :: Nehalem Memory -- 6 Is Better Than 8 Sticks?

Last night Lloyd Chambers of [URL] tweaked his DigLloydTools app (DLT) that we use to test memory throughput. It's now more accurate. The bad news is that it showed that when we put 8 sticks of memory in the 8-core 2.26GHz Nehalem, our throughput for memory read/write (memmove) dropped by 1/3. It turns a triple channel memory bus into a dual channel memory bus.

Specifically, in our test, the combined read/write throughput dropped from 9261MB/s to 6195MB/s when we went from 6x2GB to 8x2GB configuration.

Now, don't panic. That doesn't necessarily affect real world app performance unless the particular app you are running is saturating the memory bus. Which apps saturate? I don't know yet. I'm running our complete real world test suite including Pro Apps and 3D Games in both the 12G and 16G config. If I find anything that's significantly slowed by the 8x2G config, I'll post it here as well as on Bare Feats.