overheating motherboard?

I need to get a few computers going to run netflix, which demands a surprising amount of power. The computer in question is an abit ax8 motherboard, antec 430w true power (also tried a newer antec 500w). video card is an ati 2600xt. One pata hard drive (started with 2), and stick of memory (corsair xms ddr400 1GB). I bought this stuff new years back and have never had a problem with it. It has had an athlon 64 3000 (1.8 stock speed) and I have had it @2.8 stable on air. I have had it loaded before on the antec 430 watt with no problems (half dozen hard drives, 2 opticals, memory slots and pci slots full etc).

So it won't run netflix @2.3. I buy an athlon 64 fx 53 (2.4 stock and MB l2 instead of 52). It is 89 watt instead of 67 (the 3000 was 67 watt).

It goes nuts with sirens and warnings. At first on and off (tried running pcmark and every time a test would start the sirens would go off and stop when the test stopped. Then it started having sirens just booting. One of the codes on the motherboard display was 26 which has something to do with pwm. The siren is hi low which I gather is voltage or heat. The processor is only 22 watts more (about 2 amps). Things start loosing power (cpu fan, usb etc). I put in a bigger power supply with 10 more amps on the 12v rail. It gets a little less but still is going nuts.

Voltages and temps look fine in software at least. I could not find spec for the pwm temp but it only got up to the 40's. I'm at a loss at this point (can not even run it to investigate). I try different memory and different memory slots.

So I figure if it might be temps, them lets find out. I aim a 5000 btu window air conditioner in the side of the case and start it up. Now its fine. I thought maybe power management but that board is rated to take the fx processors. The cpu ran into the 50'sw under load (never reached 60). I know thats a bit hot but its rated for 70 (can not find my artic silver so I used some aero cool stuff just for now). I can not see that causing power losses and crashes.

Does anyone have a clue?

well, if sticking an ac unit up against the side of the case stops the problem, then it's obviously temp.

Sounds like your case airflow bites. get a different case, or more fans in the case, or something. cause running the ac unit on the MB isn't a solution.

The case isn't the best in the world but its not the worst. Its an old antec performance series full tower. It can take 3 80mm fans in the front (only 1 right now as I'm working on it). It has 2 80mm fans running in the back plus the psu and a pci slot fan pulling air out. I have been working on it so both case sides have been off. I have had a couple of those cases for years and never had problems like this. I tried hand holding a 120mm fan blowing on various parts and that made no difference either. If I could figure out what was over heating I could probably figure out a way to fix it.

ripit said:

The case isn't the best in the world but its not the worst. Its an old antec performance series full tower. It can take 3 80mm fans in the front (only 1 right now as I'm working on it). It has 2 80mm fans running in the back plus the psu and a pci slot fan pulling air out. I have been working on it so both case sides have been off. I have had a couple of those cases for years and never had problems like this. I tried hand holding a 120mm fan blowing on various parts and that made no difference either. If I could figure out what was over heating I could probably figure out a way to fix it.

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could be any number of parts... you're probably going to have to simply measure the temps in their by hand. The most likely issue for an old Athlon system would be the North Bridge. Check the PSU as well. Finally the GPU and CPU, though both of those generally have some form of temp monitoring...

After that it might be the ram... once upon a time ram could get pretty hot... not so much of an issue with DDR3 but it used to pop up from time to time.

The good news is generally you should be able to fix it if it's something getting too hot. For example, you CAN stick a better heatsink on the NB (if it even has one... if not, you can put one on it). just figure out what's baking.

The case isn't the best in the world but its not the worst. Its an old antec performance series full tower. It can take 3 80mm fans in the front (only 1 right now as I'm working on it). It has 2 80mm fans running in the back plus the psu and a pci slot fan pulling air out. I have been working on it so both case sides have been off. I have had a couple of those cases for years and never had problems like this. I tried hand holding a 120mm fan blowing on various parts and that made no difference either. If I could figure out what was over heating I could probably figure out a way to fix it.

I was hoping to narrow it down a bit. This system was running fine and temps were fine as of 2 days ago (and has ran fine for years). It had an athlon 64 3000 which is a 67 watt processor. I changed to an athlon 64 fx 53 that I just bought off ebay. That was the only part changed and the problems started.

I have done the following to trouble shoot. The stick of memory in it has been over clocked a decent amount and ran fine. I would think it should be able to run stock fine. still, I tried a different stick of memory and it didn't fix it.

I'm under the impression that this gen of cpu uses the 12v line from the power supply to feed the cpu (with the voltage stepped down of course). I switched to a bigger power supply that was running as of that time in another system fine. The new power supply has an additional 10 amps on the 12v line (which should easily cover the 2 amps extra the new processor takes).

Would changing the cpu make he video card suddenly over heat? I do have another video card I can try.

I'm not sure what is left except the motherboard or the cpu? The cpu being used off of ebay is suspect but it runs fine with extra cooling (the air conditioner). Temps in software are acceptable. This board actually reports the old cpu temps higher than actual temps (a known issue with this board). Still, maybe this cpu is diffrent. I can dig out a better heatsink (assuming I can find the right mounting hardware for socket 939). I have a giant scythe tower heatsink if need be (the kind that weighs 2 lbs+, and must be suspended so it doesn't break the motherboard). I think I have 939 hardware for it.


As for the motherboard, I think its really suspect. North bridge? pwm (pulse width modulation that controls voltage), but I don't even know where that is or what it looks like. The motherboard did throw a code 26 which has to do with pwm so it is highly suspect. I have no idea if its temps are being reported properly. Any of the other power management parts of the board (not sure what they would look like though I did try a fan on the larger group of capacitors andit didn't help). The northbridge has a decent size passive cooler. It wouldn't be hard to get a fan on it. I have a box of various size heatsinks for other things ranging from tiny ramsinks to big ones.

Is there anything else on the motherboard that would be suspect? What does the pwm look like?

The motherboard did throw a code 26 which has to do with pwm so it is highly suspect. = It surely could throw a code 26 if that is a PWM code and you have overloaded the PWM circuit with the more power hungry cpu.

RGone said:

The motherboard did throw a code 26 which has to do with pwm so it is highly suspect. = It surely could throw a code 26 if that is a PWM code and you have overloaded the PWM circuit with the more power hungry cpu.

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ahhh I didn't read this part... the PWM? that's not quite the NB... it's the part inbetween the NB and CPU... its the mosfets near the CPU... you CAN stick heatsinks on them if they don't have them... though no promises that will fix the problem. As it might be that MB can't handle the increased wattage of the new CPU.

Check out how easy it would be to stick a few heatsinks on the mosfets... and maybe a fan positioned to blow onto them. might fix the issue...

The first thing I thought of was, is that FX on the cpu supported list for the board. What exact model AX8 board, I did a little searching and the only AX8 board that supported the FX 53 is the AX8 v2.0.

Mandrake4565 said:

The first thing I thought of was, is that FX on the cpu supported list for the board. What exact model AX8 board, I did a little searching and the only AX8 board that supported the FX 53 is the AX8 v2.0.

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Mine is the ver 1.0. I knew it wouldn't take a dual core but the original manual says its compatible with fx processors. I'm talking about the original printed manual that came with it. That would kind of suck if its not compatible.

azanimefan said:

ahhh I didn't read this part... the PWM? that's not quite the NB... it's the part inbetween the NB and CPU... its the mosfets near the CPU... you CAN stick heatsinks on them if they don't have them... though no promises that will fix the problem. As it might be that MB can't handle the increased wattage of the new CPU.

Check out how easy it would be to stick a few heatsinks on the mosfets... and maybe a fan positioned to blow onto them. might fix the issue...

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Thanks a bunch. It has at least a dozen mosfets. I guess I could cut some ram sinks in half (the mosfets are pretty small). I just hope its not incompatible since its a ver 1 board.

I think this one is going to have to get set aside for a while till I have free time to play with it. I have other computers torn apart I need to deal with and can dig out parts for another. It is now doing it with an athlon 64 3400 and the original athlon 64 3000 that was working fine. I just now tried switching from ide channel 1 to channel 2 for the drives and the problem has gone away (with the original athlon 64 3000), but with everything else I have tried, even when it quits, it comes back. All I can guess is the higher power requirements of the fx processor fried something or I am missing a problem that is unrelated to the cpu.

The fx was a used cpu off ebay. Could a damaged cpu have caused damage to the motherboard?

I'm not sure if anyone is paying attention to this thread anymore but I got it partly worked out (maybe completely). Now I need a brick to hit myself in the head for being so stupid. So here is what the biggest problem apparently was (drum roll......)

Heatsink fan speed. The motherboard was controlling the fan speed and intermittently turned it down low enough to set off its own alarm. I have no idea why it hasn't done that for years but suddenly started now when I decided to change the processor. I'm thinking maybe I didn't have cool and quite enabled so it didn't drop the fan speed? The alarms are gone. I have no idea about the intermittent buggyness of the usb but I have ran pcmark, 3dmark etc with no alarms. I can reliably make the problem start and sotp by playing with the bios fan settings. I realized that when I changed a cpu and clear the bios via the jumper, it had no problems till I loaded fail safe or optimized bios settings.

I did change one other thing so maybe that had an effect. I looked for bios updates and saw that an update allowed for e stepping processors. It had the original 1.1 and I changed it to 1.4. I could have sworn thinking back the original bios, it had 2 logos. I can not be certain. The new bios has an athlon 64 and an athlon fx logo on the splash screen so apparently it does support the fx. MAybe the bios update did fix a bug or something. Anyway its been running the fx for hours and no problems so far.

Funny thing is, I dug out parts and got another dual core rig going so now all this will be use for is the kids web browsing and playing online games (as in little speed needed). I guess I could overclock it till it catches on fire just for the fun of it (first unlocked processor I have owned though I did get an athlon 2 x3 to unlock to an x4 stable).

Good thing you have it all sorted out now, maybe pick up a better heatsink and then you can turn C&Q back on.

Mandrake4565 said:

Good thing you have it all sorted out now, maybe pick up a better heatsink and then you can turn C&Q back on.

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Thanks for the input. The problem isn't heat or the heatsink, its the cpu fan rpm. Even though the temps didn't seem to be high enough to set off alarms, I switched to the biggest heatsink I have (I tried everything imaginable trying to fix the problem). Its a gigantic skythe tower heatsink with a 120mm fan. The side of the heatsink is about the same size as the 120mm fan if that tells how big it is. The problem is the 120mm heatsink fan is rated to run 324-1200 rpm +/- 10%. The default alarm value for fan speed in the bios is 1200 rpm (with cool and quite disabled it was running in the high 1200's so I guess its right at the alarm point). I just disabled the fan alarm for now (though I would guess I might be able to change the settings to change the alarm point too).


Temps were in the high 50's but within an a hour or two were in the low 50's in the bios. Speedfan is showing it in the low 30's though. I very clearly remember this motherboard having a known issue with high heat readings (something to do with if it was taking it off the motherboard diode or the cpu one, for everyone with this model board, not just mine). I'm guessing speedfan is probably correct. I also got lazy with the heatsink grease as I changed the cpu several times. It had some white silicone grease from the previous processor (partly hardened or cured or whatever). I just left it on the heatsink, added a tiny bit of areocool to the new processor (to let it mix a bit) and slapped it on. I can not find my artic silver so but I'll apply it properly when I get more (or actually I'm thinking of trying ceramique or artic alumina).

Now to figure out why the multiplier won't change (set it to 13 in the bios but its still showing 12 in cpuz). Its not like its a rush or it matters. At stock speed its plenty fast for what its being used for now. I originally wanted to use it to play netflix (needed 3 computers that could and 2 more that didn't need to). Its amazing how much power netflix takes to run. I build another for the third one that has a dual core sempron (pcmark05 shows it at about 4600 and shows the athlon fx53 at about 3300 so I'll probably never get this one faster than that one anyway). The other two are even faster than the dual core sempron so this would not be a candidate to replace them either. I guess the kids can browse the web really, really fast on this one!!!