I have a GA-P35-DS4 mobo with 4 gig of DDR2-1066 RAM.

When I set it on stock speeds - 9x266 (cpu) and 4x266 (ram), the memory's SPD comes up as being 1066. But if I try to set the core frequency to something higher (have tried 300 and up), it reports the the spd as 800.

What is this about? The board has 2 strapping frequencies for a 4x multiplier - 800 and 1066. I assume that at 4x266, its using the 800 strapping. If so, then the reported spd can't have anything to do with that.

Plus, if I do set a higher core frequency, I do get better throughput according to memtest - almost 5gbps. BUT . . . in every case, the machine with spontaneously reboot. So you would think that the problem is either instability with the cpu or the memory. But in almost every case, the cpu is solid. And for the couple of cases I've tested with memtest, the memory seems stable too.

For reference, at any setting other than stock, I've set the cpu voltage to 1.375 and the ddr2 voltage to +.3 (=2.24 - or so I've read). The ram - Wintec - is rated for 2.2 volts. In most cases I've left the other setting alone although in a couple cases, when I tried to increase FSB or MCH by between .1 and .2, it seems to have aggravated the instability.

I posted a simlar question a couple days ago but only got one response. I would really appreciate the help.

Thanks.