Hello
I am relly confused what is the problem with these combination!
At default BIOS setting My MB detect RAMs as DDRII 400 and set the timming as low as 5-5-5-18 and everything work well.
My RAMs are DDRII 800 and timming is 4-5-4-11 and the mushkin site says that the default Vdimm for them is 2 - 2.1 V .
I set my memory manually in BIOS at 800 Mhz and 4-5-4-11 and
V dimm to 2.15(I have set anything between 2 and 2.2 V) and my system is unstable(hanging, blue screen or crushing out of gameplay).
Now I have set my memory at DDRII 667 and 5-5-5-18 and 2.17 V
and it just work completely stable.
I have paid money more to have a DDRII 800 with low timming but I could not use it at that rate.I am really angry.
What do you think of this problem?!!!!
Mb: DFI NF590 SLI-M2R/G (BIOS is upgraded)
CPU : Athlon X2 5600+
Memory: Mushkin DDRII Bus 800 4-5-4-11
PSU: 680 Watt EPS
VGA: Asus 8800 GTS 320Mb
HDD: 2x120 Gb SATAII Samsung

Have you run Memtest86 to check for errors?

No,But now I have it to run on my brother's system (his MB is ASUS p5wdh).
they run without any problem on the real specification of the modules and the overall system is completely stable.

Test them with memtest anyway, if they pass it's PSU or motherboard problem. Did the bios update go smoothly?

I have no problem with a pair of Twinmos memorys. Don't you think of any incompatiblity with Mushkin's pair and this DFI board?

And yes(I am sorry. I did not notice your question about BIOS upgrade) The BIOS upgrade have done very easy and smooth.

I send this shortcut about my memory as it maybe useful:
http://www.mushkin.com/doc/product [...] asp?id=519

It could be a compatibility issue I suppose, but I'd still be more inclined to think the memory is faulty, that's why I'd run Memtest on it first, very quick and easy to do so worth the effort