my PC has 256mb pc2700 DDR ram and is running on Windows XP Pro. Ive got a new MSI KT4 ultra motherboard with a via KT400 chipset. Got a AMD Athlon XP1900 and put it in and when booted it was reading only 1200hz. I went into the bios setup and increased the FSB speed from 100 to 133 and then when booting it was reading 1900hz. But now after running windows for about 10mins the pc reboots for no reason and keeps on doing it. But when I change the cpu speed in the bios setup back to 100 the PC is fine but is then only running at 1200hz. Ive got a cpu Coolermaster Xdream heatsink and fan and the cpu temp is running at about 109f\43c which seems ok. Ive only got a 2mb S3 Trio pci graphics card (I know dont laugh) but its only until I got my AGP 8 geforce 4 graphics card. there doesnt seem to be any jumper settings on the motherboard to change the fsb speed, so why is it that when i under run the cpu at 100fsb - 1200hz its fine but when running it at the correct speed 133fsb - 1900hz it keeps rebooting, is it my old 2MB graphics card, is it the cpu overheating, is it me setting up the fsb speed incorrectly or what....any help ?

2 things install the PC Alert 4 software that came with your motherboard its on the motherboard drivers disc yes those temps r too high for me and yes you need a better video card i have the same motherboard mines brand new and it kicks f---in ass its a great board but u need a better HSF=heatsinkfan i recommend anything from a volcano7+ to a volcano 11+ and make sure you set all the settings right in bios cuzz u gatta turn everything on (if you havn't already) hope this helps good luck

109 F is majorly cool!!! Even my Athlon T-Bird 900 mhz is warmer than that, usually at 113 F or 111 F during idle. Your problem may be caused by using a motherboard that has incorrect voltages and/or an underpowered power supply.

The coolermaster Xdream has a pci slot at the back of my machine to adjust the fan speed. Ive got it at the highest setting and now its running at 102F. its designed to run upto AMD 2800+. my PSU is 300W, is this enough and Iam still not sure what I can do to stop my pc rebooting when running FSB 133 as the board supports 333FSB ?

Iam sure my heatsink\fan is OK. The coolermaster Xdream has copper cylinder and runs at 4800rpm and 62.8 CFM, very similar to the volcano 9+ anyway

Why does everything turn into oh my temp is cooler than yours? For one you guys should have picked up that the XP 1900+ is not meant to be run at 1900Mhz like he thought it is really a 1600Mhz chip. Yes, his fsb should be 133. I'd check to see if the multiplier was the correct number and set my fsb to 133 to the correct speed of the chip. Xp 1900+ is just the label for the equivalent of a pentium4. I believe the settings for the chip should be: fsb 133 X mult 12 And if you'd like to know XP 2400+ OC'd at 12.5 X 168 2100Mhz Temp 36C/96.8F Volcano 9 with coolmod speed 2900rpm

Methos, I think your advice worked. Ive changed the FSB to 133 but also changed the clock ratio to X12 and so far it hasnt rebooted. Sorry about the confusion with the cpu speed. I already knew that an XP1900 runs at 1600hz, what I meant was on boot up it should be reading XP1900 (even though it runs at 1600hz). temp is running 105F which seems fine despite everyones comments about temp this and temp that. Thanks for everyones help in trying to solve my problem.