My horrible AMD upgrade: Where did I go wrong?

Did the system work fine with the previous CPU with nothing else changed? Are both CPUs single-core? Have you considered that the 3000+ is simply a defective CPU? Many purchases from Ebay are faulty...

Maybe the reason it's on e-bay in the first place is because someone overclocked it until it blew? Never buy things like video cards and cpus second hand unless it's from someone you trust.

Your new CPU hould work fine on that mobo unless it's defective. Reinstall the old CPU and see is it works again. If it does, you probably just got a bad CPU off ebay. Good luck getting a replacement/refund.

on your mobo their will be a jumper, set it to 333mhz fsb, that is your problem, amd boards don't detect their cpus via cpuid, they do it via clockspeed.

Have you done what megame255 said and replaced the old cpu? What about disabling SATA in the bios and trying to install like that? XP can have some issues with SATA, even if (like you) you have the drivers.

Is that Memory Frequency?

What would it be under in BIOS?

I did and I was able to re-install w/out a hitch.

Great! But which bit did you do? The old cpu or the SATA thing?

The old cpu

I would increase the memory voltage to 2.7v and maybe add a .05v to the CPU. since your system is old, maybe the PSU is not up to the task, so increasing voltage may help to stabilize the thing. If you can try a newer PSU, this would help to see if it is a power issue.

"It's working! It's working!" - Anakin Skywalker The Phantom Menace

I had to go with the following settings...

CPU Speed [1750MHz]
CPU Frequency Multiple [10.5x]
CPU External Frequency [166/33]

When I was able to log into Windows the "My Computer" stated it as...

AMD Athlon XP 1600+
1.75GHz, 1.50 GB of RAM

I wonder why that is. Can they physically fake a CPU look like a 3000+ Barton?

no - your CPU is just working at half speed.
A CPU clock on socket A is determined with the following formula:
Front Side Bus x Multiplier = operating frequency.
Mot CPUs have a locked multiplier - varying the frequency is thus done through FSB modulation.
Moreover, RAM speed is usually sync'ed with the FSB for best performance - and may work at 166, but not at 333...

Your CPU's original settings should be:
333 x 10.5 = 3496 MHz (rounded at 3500)
However, that far too high for an Athlon XP; it should only be
233 x 10.5 = 2446 MHz (rounded at 2500 MHz) rated 3100 compared with original Athlon's speed.

However, it seems that your CPU or your memory is unable to hold its normal frequency. Reducing the FSB to 166 yelds:
166 x 10.5 = 1743 MHz (rounded at 1750).

This may come from several points:
- you haven't connected the square 12V connector on your motherboard
- your motherboard has leaking voltage regulators, making it unable to hold such high frequency
- your RAM is set on a 1/1 ratio with FSB, and can't work at 233HMz (no DDR from the days of Athlon 1333 can - duh!)
- your PSU is too weak to hold the load
- your CPU got sunburnt (overclock) and can now work only at reduced clock speeds.

My advice: first try a new PSU (can't hurt: you should change it once in a while), don't forget the 12V line, then try locking the memory speed at a lower ratio (FSB 3: RAM 4, or Memory speed = FSB -33%) and running the CPU at normal frequency.

If it still fails, then go back to a lower clock speed (1750 MHz) and tighten your memory timings (1:1 FSB/memory ratio, lower CAS, lower RAS...).

The Athlon XP 3000+ is a 2.166 GHz CPU with a 166 MHz FSB and a x13 multiplier. Increase the multiplier if it allows you to do so to the CPU's max of x13, which will generate the correct speed and ID for the processor. If you cannot change the multiplier to x13, then the CPU was not a 3000+ to begin with.

Unfortunately, if you are able to change the multiplier, that means the CPU you have has been modified by its previous owner, likely for the purposes of overclocking. Overclocking can damage a CPU and cause it to behave erratically or stop working altogether. To check for modifications, look on the bottom side of the CPU for any wires, lines of solder or graphite, or other suspicious material linking any two of the pins together (all of the pins should be electrically isolated on the bottom of the CPU). You may not find anything, but that doesn't mean the CPU wasn't tampered with.

As a side note, it is normal for Windows to mis-identify over- or under-clocked Athlon XP CPU's, as it relies on the clock speed of the processor for ID.