Possible Pentium III Trouble (I think I might have messed up bad)

edited September 20 in Hardware

A few months back, I purchased a Gateway Tabor III motherboard on eBay. It had weird front panel I/O (HDD led, PWR led, etc.) issues because it used a proprietary connector, but I got that all figured out, and it was running great.

Well.. kind of. It would have weird bugs with AGP cards, I have an nVidia GeForce MX2 400 card, and it would work on other motherboards, but not the Tabor III. I thought it was an issue with the motherboard and the card, as I put a nVidia Geforce FX5200 in it and it worked fine, though I was irritated because it was supposed to be a 2001ish rig, which the GPU fit date-wise. I mention this problem because it might have something to do with what I may have seriously screwed up on.

When I got the motherboard, it came with a Pentium III Katmai 500mhz. Keep Katmai in mind.

I had a Pentium III Coppermine I kept over from a different, albeit crappier Slot 1 motherboard. (No AGP, figures.)

In my excitement to have a PIII Desktop system, as soon as I got it I upgraded it.

A system with an intel 440BX chipset. With a Coppermine. I just realized this tonight, and not only that, but I had been using the system quite a bit before. Never saw any problems, it booted up fine, and the system even recognized what it was, but when I was going over the differences between my Katmai and Coppermine, I found that Katmai uses 2V, and Coppermine uses 1.65V.

I want to know:
A) How badly damaged the processor might be (the Coppermine I put in it). The system hasn't been on for something like a month, but it smells.. weird. Like chemical. I haven't tested to see if it still works.

B ) How badly damaged the motherboard might be. This is my only decent PIII motherboard with AGP, as well as many more PCI slots than the other crappier board has, and even a single ISA slot.

When I realized the voltage differences, my heart sunk. I don't know the lengths of the damage, if there even is any at all.

The Tabor III is from around.. 1999? I think.

I can give a specific model number if it's important.



  • Probably didn't damage the motherboard. The BIOS decides what voltage to feed the CPU; the CPU can't just demand more -- either the BIOS supports what the CPU wants and provides it, or it doesn't. Some CPUs aren't fussy and can run on a range of voltages (increased voltage in fact is used in overclocking); others are picky and only work with one. Some motherboards are very flexible and support a wide range of voltages; others only have a choice of one. Sounds like yours is of the flexible variety. If either board or CPU was actually damaged, it would just quit.

    Intel CPUs of that era can take an astonishing amount of abuse (in fact, I have yet to see a dead one in literally truckloads of salvage). Worst case I've seen: I was gifted a "crashy" P3-500 that had a seized-and-clogged CPU fan -- the whole assembly had been so hot for so long that the fan crumbled at a touch, and everything was warped -- I had to use, I kid you not, vise-grips to pull the CPU card out of the slot. The motherboard had been heat-flexed so much that it was shorting from broken traces and was decreed dead, but I used the CPU to upgrade one of my PCs -- gave it a proper HSF, and tho it initially played dead, after a few minutes it suddenly came back to life -- and ran 24/7 for the next ten years with ZERO problems (in fact XP ran for 8 years with only two reboots, and that box did all the heavy lifting. Yes, it routinely had uptimes in excess of 2.5 YEARS.)

    Funny smell, tho, that could be capacitors starting to leak -- lot of 'em from that era are starting to go bad from sheer age, and your first clue is a sort of burning-damp-basement smell. Fortunately, if you're good with a soldering iron, capacitors can be replaced.

  • Forgot to mention, generally if voltage is out of its acceptable range, the CPU will simply refuse to power up, or will lock up almost immediately. Running fine for a while? Then no worries.

  • I do admit I was a little panicked when I made that post.

    I didn't think there were capacitors on Slot 1 processors though. Funnily enough, the 600MHz one I got had a pretty bad off fan as well, it was very loud and ran slowly. There were no other fans in that case. I'm going to see if that had anything to do with the AGP card issue- the fact, however, that the motherboard recognized the processor as a 600MHz, makes me think it did work, though maybe not as well as it could've. I forgot that I had given it a BIOS update from the year 2000; probably why it knew what the processor was in the first place.

    Thanks for the advice.

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