P5Q Deluxe dropping FSB speed?

Hello. On two occasions, earlier today and two days ago, when setting up my FSB to run at 452 MHz, booting into Vista64 and running Prime95, I would note Everest Ultimate reporting the FSB having gone down to 448MHz. (As I rebooted both times and discovered the BIOS still thinks it's 452MHz, I am confounded.)

I am testing my system right now, at 451MHz:

Q9550 @ 8.5x451
vcore 1.36825v
gtl 0/2 = 0.675
gtl 1/3 = 0.685
CPU PLL = 1.56
NB = 1.4v
FSB Term = 1.30v

CPU Spread spectrum = disabled
C1E = disabled
Speedstep = disabled

Also, when I manually set my FSB Strap at anything other than AUTO, memtest86 reports constant errors. I noted this strapping, when set, brings up other values in "DRAM FREQUENCY" -- given many of these settings are the same, I do not know why 400 or 333MHz might lock up yet 200 won't, assuming "AUTO" chooses 200. Why might that be happening?

Could this be a bad CPU? Or motherboard? Or another BIOS setting I'm overlooking?

Thx!

When its on auto the FSB strap selected is based on the DRAM freq you choose.

333 strap gives you certain DRAM freq options, and 266 strap gives you other DRAM freq options, etc. Auto strap gives you all the DRAM freq options, and depending on which DRAM freq you select will dictate the strap chosen.

Did you try disabling USB legacy support before running memtest? Remember that memtest will also fail if your NB isn't stable. Have you tried lowering your NB volts, or does that make it worse?


If you could POST ALL your BIOS settings that might help.

I've see fsb jump like 1mhz or so when testing and total cpd speed moves a few mhz, but 4mhz moving on fsb seems more than usual, but I don't have that board or cpu though ... so ...

i have this board, and i notice one megahertz sometimes, in CPU-Z it flickers at 3599 and 3600. I also notice that the bios will, on POST, say 3.62, when in fact its 3.6, and says so in vista/CPU-Z - for some reason. But 4MHz - a bit strange to me.......