Testing / comparing : Intel D975XBX2 / Asus P5B DX ***56K WARNING***

[gtj]

Setting say FSB to 400... Then running 266ref and mem at 533 gives you DDR2 800 1:1 but if you set 667 it gives you ddr2 1000 4:5 and if you keep the same timings and FSB of course its going to be faster and have lower latency you changed the memory frequency to 500 instead of 400. Or am I reading what you said wrong?

Exactly.
At 400 MHz, your FSB thoughput is 12.8 GB/s.
At 1:1 your memory throughput is 6400 MB/s.
At 4:5 your memory throughput is 8000 MB/s.

It's simple math. 8000 is better than 6400.