I've perused the forum and seen many issues similar to mine, but regretably no solutions that have worked.

Problem: My Athlon XP2100+ is detected as an XP1500+ on POST.

Gear: MSI KT3 Ultra2, AMD Athlon XP2100+, 1 stick of 512MB PC2700 333MHz DDR, Maxtor 60GB 7200RPM DiamondMax etc.

I know that I should be running with a 166MHz frontside bus for that RAM, or at the very least a 133MHz bus to achieve that 1700GHz that my CPU is supposed to put out. Unfortunantly, I can't even get the display to work or the system to POST upon changing the FSB!

I used Fuzzy Logic (a nice little overclocking tool) to try and "overclock" the 1300MHz that I AM getting and it could only take it up like 50MHz before crashing.

I tried to switch up my 350W Enermax P/S with a 300W I had lying around and the same issues were present.

...and heres an interesting one. I took a perfectly good Athlon 1.2 GHz out of a neighboring system and it underclocked to 900MHz!

Now I think that that all boils down to the multiplier and the FSB clock, but as I can't seem to change it without having to wipe the CMOS afterwords, I could really use some suggestions!

Anybody solved this issue? I'd suuuper appreciate some feedback.

First thing is the FSB should be at 133 MHz for your CPU.

If you don't get any video when you change the FSB to 133 MHz usually the probably is down to a weak PSU or dodgy RAM but these two components should be fine for your PC. Have you tried with just the Video card/CPU/RAM and PSU hooked up?

I'm just curious to know what the voltages are on that Enermax 350W PSU, on the +3.3V, +5V and +12V rails.

If I was in this situation after trying different components I would think about RMA'ing the board. One thing I would do before is, if you can, test the 350W PSU out with another system with a similar specification as yours. It could be that the PSU isn't regulating the voltages properly and that 300W was just too weak anyway to supply enough power to the board and it's components.

Your memory has it's own speed settings in the BIOS...you don't wanna run your FSB at 166mhz, you wanna run your memory at 166. Check your DRAM timing control settings in the Advanced Chipset Features. Make sure your Frequency is set to either HstClk or HstClk+33...if it's set to HstClk+66 & your FSB is at 133, you'd be running your memory at 200mhz! Try setting your FSB to 133, your memory frequency to HstClk & see what happens. You can always bump it up to HstClk+33 later.

Also update your BIOS!

Thank guys, for the prompt and concise replies... I went through each of your recommendations with the following results:

- the BIOS was already the latest version (via Live BIOS Update).

- When I tried to run the system with only the VID/CPU/RAM and PSU hooked up I was able to successfully reach the BIOS (as usual), but as soon as I opted for the 133MHz bus speed, it refused to POST (or show any signs of life beyond the power LED) again.

- I checked on the DRAM timing and it was set by default to "SPD", so I changed it to HstClK and HstClk+33 in turn and with FSB at 100MHz and 133MHz, but got the same dead-on-reboot result.

- Checking on the RAM, I ran Memtest86 and though I only gave it a few passes it checked out OK.

- The only other thing I can mention is that the little diagnostic lights on the MSI's D-Bracket indicate "an improperly installed or damaged CPU" when the system boots as an XP1500+. In the later case, I might add, everything seems to run OK... as a 1300MHz system.

*sigh*

What component(s) should I take back?

Well, that was weird...
If you say that your CPU is damaged is quite likely to change it, although you don't seem to have any luck since it's one in 1000000 that are damaged or something like that anyway if nothing of the suggestions above worked I would really try changing one or more components, as far as I understand the problem lies in your mobo, but I'm not quite sure...

you could also unlock the chip, then set the multiplier to what it's supposed to be at.

I've had this problem with MB being crapheads.

Just set everything to Auto and/or jumperless and try it.

The Mb are supposed to automatically detect the CPU and set the right speed.

Im having the same problem with my xp2100. I have the MSI KT4 ultra... maybe its an MSI thing? In another post, you said that on boot up it used to read xp2100+ and now it says xp1500+. mine has read xp2100 since i installed it. when mine freezes, i can just restart it to get it going again. i dont have to pull any jumpers. this is pissing me off as well... if i wanted a xp1500, i would have bought an xp1500 dammit! if you find out the fix for this, please post. thank you.

Sorry if this post is too late, I have a KT3 Ultra ARU, running an XP2100+ perfectly. You should try resetting the BIOS properly (take out the battery with the PSU leads disconnected and leave it for half an hour). I got mine working brilliantly, then I got fed up with the heat that made the fans so damn noisy so I deliberately underclocked it to XP1500 (1.3Ghz) and everything works great (15°C cooler as well) and MUCH quieter, thanks to Zalman Fan Mate 1s. There is no noticeable performance hit on XP Pro SP1, and I strongly recommend you leave it as XP1500, it's worth it because of the heat and noise.
If none of this has helped, try persuading your supplier to allow you to upgrade to the KT4 BSR. That board rocks, and it's likely to be my next upgrade move.
Good luck,
Simon

I had the same problem with my Athlon XP 1900+ in my MB Soyo Dragon Plus and my new MSI KT4 Ultra. After many tests during 8 weeks I found the problem.
Because I change de position of the clip of the cooler (turn 180 degree), for better position during the instalation of the cooler. This make some effors in the socket that make some bad contact.
The last end of the clip to hook the latch of the Socket must be point towards the lever pivot of the socket.

Sorry my pour english.

Fan. from Argentina