I'm currently using the F5 bios on this board and I cannot figure out how to manually change the Memory Frequency under DRAM Performance Control. In the manual it says the Memory frequency is automatically adjusted according to the CPU Host Frequency.
However, my ram is DDR2-800, but I want to set the FSB for the CPU higher than 400 without overclocking the ram. Every time I change FSB the memory frequency changes with it and I can't lock the ram at 800.
There will be a setting in the BIOS that has to do with memory frequency multiplier and/or memory "latch" speed (whatever it is labeled in your BIOS). You need to turn this off from the auto setting (manual) and you will be able to set the ratio accordingly. A ratio of 2.00 will give you 800mhz ram. I believe 2.00 is the lowest ratio possible. Any FSB over 400x4 will result in your RAM pushed past 800, your RAM will hold you back. If you have to use that RAM (although 4GB of 1066 is very cheap these days), only thing you can do is loosen the timings and see how far it will let you go.
This is true; FSB x MCH mult = DRAM speed, and 2.00 (1:1) is the lowest available; note that, if you're pushing it, the 2.00D (1600MCH strap) mult will give you better results than the 2.00A (1066MCH strap) - the strap latencies are higher, and therefore, more tolerant...