Porty try one stick seperately plz... with memtest you mean the one in DOS ? or the one in windows ? also try to lower ya volts to 1.92 for the ram , that's 2.0 volts in reality which is enough for my Gskill kit for 1002mhz operations...
Small FFT's is solely CPU test, blend does a mix...

NB voltage shouldn't be needed to be over 1.26... for 400FSB/1002 ops... and eventually try the new beta bios I'm on it seems stable (so far), onyl weird thing now is that my LAN ports need more time to connect to the internet... (or is this a coincidnce with my ISP)