FSB > 100Mhz impossible?

On one of my systems (main system), I don’t get any post when using a CPU FSB over 100Mhz. Quite absurd, as the board is designed up to 200Mhz and my CPU can do 133Mhz.

Whatever I do, I can’t get the FSB over the 100Mhz barrier. I already tested memory etc etc and everything works just fine!

My CPU runs at 29C (stressed) so that shouldn’t be any issue…

Anybody an idea?

System specs (full specs see sig):
Athlon 2100+ (TBred-B 133Mhz FSB)
1Gb PC2700 PQI RAM

Is there a FSB jumper on the board?
Standard procedure is to reset CMOS, reset default settings, etc.

Originally posted by rdgrimes
Is there a FSB jumper on the board?
Standard procedure is to reset CMOS, reset default settings, etc.

Yeah I know, already did that…

Safe mode (100Mhz) works fine. Normal mode with FSB set to 100Mhz (BIOS) works fine as well.

I’ve got my system running at 133Mhz right now, but the way I did is rather strange: I pulled the PIV power connector (4 pin) from the board! I read about this on some site I found with Google… going to run Prime95 now…

i seem to remember that some ppl who had fsb problems with their nf2 boards simply pulled off the fsb jumper, which solved the problem.

Well everything seems to be working fine again!

What I did?

  • unplugged the P4 powerconnector (should be there for extra stability, but doesn’t allow me to post)
  • downgraded to BIOS 1.2 (with RAID mod)
  • fitted my northbridge with a bigger heatsink (i noticed the fan on the small heatsink died, put a big heatsink on it now)
  • overclocked my cpu to 2700+ again, 3d mark and prime95 are running for quite some time now without a problem (cpu 50c fully stressed)

Great… :slight_smile:

(I just wonder why unplugging that connector does the trick!)

I just wonder why unplugging that connector does the trick!)

That’s a 12v power lead, how’s your 12v rail looking for voltage? the obvious answer, apart from a funky board, would be a funky PSU. You wouldn’t by chance have 13 drives hanging off it would you? did you try it with everything disconnected?

Well my 350W PSU is quite heavily loaded, but the readings from the 12V line are the same as with an Antec Truepower 400W PSU (I have 3 hdds and 4 opts, radeon 9700 and oc’ed Athlon XP): about 11,8V. The system seems to be stable, so let’s see what it does for a week or so. Still, it’s pretty strange…

Some PSU’s don’t allow full load on one rail, unlike the Antec True, they will crap out when one rail is loaded. You’d have to check the volts with a multimeter to really know what it’s doing, but disconnecting everything would answer the question of whether it’ll POST. Since you’re running now with the OC, it’s just a curiosity. My Antec True-550 runs solid at 11.95 with everything under the sun connected.

I might check the voltages when I find the time for it. For now I am satisfied, as Prime95 is still running (about 23 hours now) and my system runs like a sun.

As soon as I find the time, I’m going to figure out why the PIV connector does the trick, I’ll keep you updated…

One other thought: I’ve read a lot of reports of MB’s that undervolt the Vcore. Increasing the Vcore one notch sometimes solves weird problems like your’s. Same for chipset volts if you have that setting.