Odd Overclocking Problem

[paulcs]

Late last week, I purchased a FC-PCA PIII 700 with the hopes of running it on a 133 MHz FSB at 931 MHz.

I bought a fancy Globalwin heatsink, silver-based grease, etc. Well I had trouble getting it to post at 133 MHz with any voltage, but absolutely no trouble at all at 124 MHz at 1.65 V.

I ran it at 868 MHz for a while, running the command line SETI client, and then restarted. At the post, I entered the BIOS, changed the FSB to 133 MHz and into Windows I went. I've ran SETI clients and a few benchmarks for two days straight, nonstop, and without a hitch. Restarted a few times. No problem.

Today, I shut down completely and turned the machine back on. No post, no nothing. I pulled the plug out, restarted and was knocked back into the BIOS, which is what Asus motherboard do if you have an unsuccessful post. I fiddled with the voltage again, trying everything from 1.65 through 1.85. No cigar. I fiddled with the memory timings and eventually installed true CL2-rated PC133 RAM. Still no post.

I reset the FSB clock to 124 MHz, and booted back into Windows. I immediately restarted, testing a theory that complete shutdowns were the problem, enter the BIOS, reset the clock, and I'm back into Windows at 931 MHz at a lower voltage then I was using before. I run SETI for a little while. No problems. Shut down completely again. No post again.

CPU temperature appeared fine while at 931 MHz: about 35C at 1.80 V and 31C at 1.70 V.

Well, it appears the CPU will run fine at 133 MHz. It just won't post at 133 MHz after a complete shutdown. I've had overclocking problems with posting in the past, as well as trouble getting into Windows, stability issues once in Windows, etc.: the typical overclocking issues. Never have I seen a CPU that will run at a particular clock speed in Windows without any stability problems, but will not allow you to cold boot into Windows.

Any insights would be appreciated. Thanks.

Paul
paulcs@flashcom.net

[paulcs]

I should give you some specs.

PIII 700 (latest stepping)
Asus CUBX (BIOS 1005 and 1006cu.3Beta
128 PC133 CL2 RAM and 256 MB PC100 RAM
IBM 15 GB HD

By the way, this exact same configuration was running a PIII 550E at 733 MHz for months. Not a single problem. This leads me to suspect the CPU, although, again, the darn thing runs fine if I restart as opposed to powering down completely and powering up.

I'm back in at 931 MHz, 1.75 V. Think I should keep it this way, without powering down, for a couple of weeks? (Maybe I'll get lucky and get a blue screen. Then at least I'll know what's going on.)

Paul
paulcs@flashcom.net

[This message has been edited by paulcs (edited 20 June 2000).]

[Brian R.]

If I were having these symptoms, I would see if the MB would successfully run the old processor at 133 fsb. If not, maybe the MB has developed a weakness. Possibly, this may also indicate the PS is strange when cold. Maybe try a different power supply.

If the old processor runs fine, as you presume, then there is a strange happening in your new processor you can't really do anything about. Another possibility if the old processor runs fine is the PS again. This would follow since the new processor draws more current, it is exposing a weakness in the PS you don't see with the old processor.

Other than the processor (no fix) or MB (no fix) or PS (replace), I can't see any other possibility.

I know this is a little daft, but if the old processor doesn't run consistently anymore at 133, could it be a BIOS problem? I have never seen such a thing, but perhaps the BIOS is corrupted and not giving a perfect set of instructions.

Sorry if all this is a little basic, but I really am in the dark.

[This message has been edited by Brian R. (edited 20 June 2000).]

[paulcs]

I don't think the BIOS theory is daft. I certainly flashed the BIOS after ruling a bunch of stuff out. No go.

I had a fairly rough time of installing the heatsink (and have some nasty cuts on my hands to prove it). I've been thinking about the motherboard being a problem. Maybe I damaged it.

Thanks, Brian.

Paul
paulcs@flashcom.net

[Maggi]

Hi Paul,

I guess this is caused by your PS ... it just struggles when it has to spin up all fans, HDs, CDs, DVDs and whatever !

Try to empty every CD and DVD drive and try again otr if you have SCSI HDs set those to be spinned up by the controller instead of system startup.

Or just buy a more powerfulls PS ...

Cheers,
Maggi

[birdy]

or have 2 psu's. it's not tricky, it is messy. It is cool

i would also check the cmos battery, the bios maybe losing settings when presented with a power shutdown. And check the yellow cable connector on the atx plug, if this is loose the mobo will appear to be alive, fans spinning etc but won't post

[LAMFDTK]

Its the blood type that you have. AB is great for O/C'n but stock, run of the mill, A type will lock you up before windows will post. Everytime.

[paulcs]

It would be ironic if it was the power supply, given that I've given "upgrade your power supply" advice so often.

I have an Addtronics 300 Watt power supply in this box (which is really made by Antec), and it has worked with a GeForce 256 DDR (which is a pig!) and another fan.

I do have a bunch of fans in this case: a 12x12 mm and 8x8 mm in the front, a 6x6 mm and the PS fan in the back, and the biggish fan on the Globalwin heatsink. Only the heatsink's fan is connected directly to the motherboard. I had another 8x8 mm fan at the side panel, right above the CPU, but I removed it.

I don't have a whole lot of peripherals: GeForce2, Soundblaster Live, SCSI card, NIC, HD, CD-ROM, floppy drive.

I just restarted (as opposed to shutting down), lower the voltage to 1.70, and ran two SETI clients simultaneously, along with Hardware Monitor Pro. It locked up after about five minutes. Back to 1.75 V.

If it is the power supply, that means there is another 400 Watt PC Power & Cooling unit in my near future. Ouch.

Paul
paulcs@flashcom.net

[Maggi]

then try 1.8 VCore ... it didn't harm my Celery which defaults to 1.5 volts.

I now run 1.85 volts and it seems that I'm now completely stable at 952MHz.

At 1.8 volts I got occasional hickups.

Remember, the higher the Voltage, the less Ampere will be drawn off your PS to reach the same Watts ...

[spoogenet]

Remember, the higher the Voltage, the less Ampere will be drawn off your PS to reach the same Watts ...

Yes, but the higher the voltage, the more current you will draw, and the more power you will dissipate. The power does not remain constant, it is a variable.

If the PS is the problem, test that theory. Yank out some PCI cards, maybe unplug the CD drives, and then check. The PS may not be the problem at all, the MB may be having issues providing enough power to the CPU on boot.

Especially with a Geforce card which is a power hog, and the Globalwin heatsink/cooler is also probably a power hog. Since your heatsink fan is connected to the motherboard header then it is drawing power from the board, which may be causing voltage or power problems in your processor when you first boot up, which could cause it not to post.

The solution to that problem is to unplug cards from your bus, maybe take one of your DIMMs out, and maybe get a less-power-dissipating vid card and give it a whirl...if that works, you've probably got MB power problems.

b

[paulcs]

Well, I stuck in a 400 Watt PC Power & Cooling power supply and it didn't help.

I'm beginning to get suspicious of the motherboard, which has two fan connectors *extremely* close to the socket, and my big heatsink fan.

Paul
paulcs@flashcom.net

[paulcs]

It was the motherboard not getting enough power to the CPU, as suspected. I stuck the CPU in a slocket, set the voltage to 1.8, installed it on an AOpen AX6BC Millenium Pro II, and booted in without a problem.

Sheesh. I would have expected better from the CUBX.

Paul
paulcs@flashcom.net

[spoogenet]

If you ARE having power problems, chances are it's not your PS's fault. If the mobo can't handle as much power as you're trying to consume, quite frankly it won't work properly.

Test the mobo by removing cards and then see if your system will POST. Preferably replace your vid card with another one that doesn't eat much power. If that fixes your problem then your mobo can't handle the power demands you are putting on it during the POST. If it doesn't fix your problem, then, well, you've got an odd issue.

b

[paulcs]

I didn't make myself clear during my last post. Sorry

I switched motherboards and it works.

Paul
paulcs@flashcom.net

[spoogenet]

Nope, you were perfectly clear. I was writing my response while you posted your next response, so I hadn't seen yet that you had tried a different mobo. My bad.

My guess is that you're vid card may be sucking too much power from the board, so you might want to give that a shot just to see if it fixes your problem....however you shouldn't have to sacrifice video just to have a perfectly working system.

b