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-   -   Fix for 8k9a undervoltage problem (http://www.aoaforums.com/forum/amd-motherboards-and-cpus/11320-fix-for-8k9a-undervoltage-problem.html)

Rudzer 23rd November, 2002 11:41 PM

Fix for 8k9a undervoltage problem
 
Would like to know if the undervoltage BIG problem on the 8k9a can be solved (with new bios or something like that)!

Thanks in advance!

Holst 23rd November, 2002 11:45 PM

I dont think a bios update is going to fix a PSU problem.

Rudzer 24th November, 2002 01:37 AM

Ok so tell me why with a 8k3a+ when I choose 1.9v it really used the 1.9v and now with same hardware but the 8k9a when I choose 1.9 it gives about 1.82v....

Jeff F. 24th November, 2002 02:54 AM

Quote:

Originally posted by Holst
I dont think a bios update is going to fix a PSU problem.
Uh... I don't think the 10 or so people who have asked about low Vcore when setting to 1.95v or 2.00v all have bad power supplies.

I've tried my 8K9A2+ with four different power supplies and three different processors and the board does not function properly at those settings.

Why don't you try it for yourself? The thread I started 2 to 2-1/2 weeks ago never was even recognized by an ET and I asked for help about as nicely as someone can ask.

(this thread: http://www.aoaforums.com/forum/showt...threadid=10736 )

Other than the low Vcore, the board kicks some major butt so I don't see why you wouldn't be interested in helping solve one of it's only flaws...

Rudzer 24th November, 2002 03:17 AM

exactly :(

Daniel ~ 24th November, 2002 04:15 AM

Not every answer is at the tip of EPoX Techs fingers or lies in their ball park to answer. Nor are they here to meet anyone's expectations. They give what help they have the time to and can. I'm Moving this post as the tone is less than it might be.

If you want a clear answer try asking a clear question.

Holst 24th November, 2002 04:19 AM

Not to mention that I hadnt considered a 0.05v drop in Vcore a major problem, It hadnt even entered my mind.

I found the 1.95v setting to give 1.95 exatly, and the 2v setting to also give 1.95 exactly.
Some slight problem there, im not sure why that is at the moment but it has been noted and if I find a fix ill tell you.

nelamvr6 24th November, 2002 08:25 AM

Quote:

Originally posted by Holst
Not to mention that I hadnt considered a 0.05v drop in Vcore a major problem, It hadnt even entered my mind.

I found the 1.95v setting to give 1.95 exatly, and the 2v setting to also give 1.95 exactly.
Some slight problem there, im not sure why that is at the moment but it has been noted and if I find a fix ill tell you.

The Vcore on my board tops off at 1.92.

And its not my PSU.

Fewture 26th November, 2002 01:24 AM

Quote:

Originally posted by Holst
I dont think a bios update is going to fix a PSU problem.
I measured my PSU. It's fine. It's the board. 100%. And you don't see 1,95 or 2,0V as a big difference? If you need the voltage and it's not there..pretty sucky :clown:
But apart from that the board is great.

btw: Jeff, I'm working on a vmod for this board. I'll let ya know if I get anywhere.

Random Nonsense 26th November, 2002 10:08 AM

Um, how are you measuring it? I know how Holst does, and I trust his results.

The on board monitoring is not exactly accurate most times.

Your complaining about a .05 volt drop off, im getting a .2v fluctuation (bounces from 1.71 to 1.91). im solid as a rock though so not overly bothered. This is on an MSI board though.

nelamvr6 26th November, 2002 01:42 PM

Quote:

Originally posted by Random Nonsense
Um, how are you measuring it? I know how Holst does, and I trust his results.

The on board monitoring is not exactly accurate most times.

Your complaining about a .05 volt drop off, im getting a .2v fluctuation (bounces from 1.71 to 1.91). im solid as a rock though so not overly bothered. This is on an MSI board though.

Actually I'm complaining about .8 volts.

I'm using MBM5 to report my vcore.

If the mobo is providing low voltage or if the mobo ir reporting voltage inaccurately either way it it a problem with the mobo.

But I suspect that the voltage really is low. The onboard reporting of all my other voltages (+5, +12, +3.3) were spot on when compared with readings from a DMM.

Random Nonsense 26th November, 2002 03:46 PM

Quote:

Originally posted by nelamvr6


Actually I'm complaining about .8 volts.


Do athlons run on 1.2 volts?

You meant 0.08 volts, still its not much, + it still works doesnt it?

Im sure that the on board monitoring components are as good as they can be without getting stupidly high prices. all boards are innacutate its a fact of life. Temp readings arent accurate, voltages arent, fan RPM isnt. its the way it has always been and always will be.

Even my £50 digital thermometer has a 3% error built in.

nelamvr6 26th November, 2002 05:29 PM

Quote:

Originally posted by Random Nonsense


Do athlons run on 1.2 volts?

You meant 0.08 volts,

Yes of course, you're right, I meant .08 volts.

Quote:


still its not much, + it still works doesnt it?

That's not the point, is it? The voltage on the board is supposed to go up to 2.0. It can't even make it to 1.95. I have already found myself in a situation where more vcore would be nice to have, and one of the reasons I bought this board in the first place is that plenty of vcore was supposed to be available, according to the specifications provided by the manufacturer.

Why bother to provide any voltage adjustment at all if not to cater to the overclocking community? We all know that from time to time during the overclocking process it becomes necessary to increase the vcore.

If my board were one of few to have this problem I could chalk it up to bad luck and make do. But it seems that many people have the same problem, and so far EpoX has not responded.

I'm not entirely dissatisfied with this board, it has many good qualities. But it has had some problems, the low voltage being just one. It would be nice if this problem were addressed, or at least acknowledged..

Random Nonsense 26th November, 2002 07:43 PM

set your CPU to stock, then overvolt it, see if that helps. if it does, i'd say all is well....

nelamvr6 26th November, 2002 09:52 PM

Quote:

Originally posted by Random Nonsense
set your CPU to stock, then overvolt it, see if that helps. if it does, i'd say all is well....
:confused:

Set my CPU to stock, overvolt it and see if that helps what? Are you suggesting that perhaps my increased FSB is somehow affecting the vcore voltage available? I find that very unlikely.

I'm afraid I don't understand what you're getting at.

If my CPU were running at stock speed I wouldn't need more vcore, the default voltage would be sufficient.

The problem is that when I want to overclock my chip I eventually need to raise the vcore, and the motherboard is not able to deliver all the vcore voltage that it's supposed to.

Unless you mean to say that by running my chip overvolted at stock speed for a time will then allow me to reach my desired OC with less voltage.

That may or may not be true, and I am slowly enjoying success by burning my chip in at the vcore that is available, but this doesn't change the fact that the board is not supplying the voltage that I expected it to.

CamoAlien 27th November, 2002 01:40 AM

Rudzer & nelamvr6 - Hi. Impressive MHz count you have there. ;)

Now, you have a very valid point about the Vcore. By all means, it should be able to reach 2.0 volts at the 2.0 volt setting. However, might it be possible that your board actually is functioning correctly, and is not failing to provide the correct voltage? Let me elaborate, using the electrical approach.

Given: You have an overclocked Athlon XP (T-bred core) 2400+ @ 2236 MHz.
You are running a very high FSB (most likely irrelevant)
You want the 2.0 volt setting to work
At the speed that your CPU is running, it is drawing a massive amount of current, and is producing a very large amount of heat (which is why they make giant heatsinks and water blocks and peltier chips).

Now, say you set it to 2.00 volts. However, it gives you 1.92 volts. This is exactly 4% under what it should be. Sure, 0.08 volts may seem like alot, but it is only 4% under.

Now think about this: you have a bunch of computers running, and all of the lights in the room are on. You pop something in the microwave, and the lights get a bit dimmer. Why does this happen? Voltage drop, and it happens when you are drawing a large amount of power (or a large number of amperes). Normal voltage for your standard wall socket in North America should be between 120 and 130 volts. Drawing a large amount of current could easily cause it to drop to between 110 and 115 volts (in other words, a 13% drop in voltage).

Similarly, at this speed, your CPU is drawing a large amount of power, and is causing a voltage drop. Those VRM's are doing their best to supply it with 2.00 volts, but they are putting out 1.92. The industry specifications for most electronics consider a 5% deviation as a low tolerance, and you are 4% below, which is within spec.

The other thing is that it might not even be the VRM's. It might even be the traces on the PCB or even heat buildup within the CPU traces that cause a wee bit of resistance that would drop the voltage a little bit.

Add to it how inaccurate the voltage sensors are in the first place, and you can see why sometimes it may appear that you aren't getting what you are paying for.


Anyhow, if you are seriously concerned about the voltage issue, it may be worth a look with a Fluke digital multimeter. You could also check the Vcore lines with an oscilliscope to watch for excessive ripple, which is another source of poor voltage regulation. Then, if necessary, either solder a varistor or use a clip-on wire on the IC which determines the Vcore (can't quote the IC # for you, haven't kept up on this one) and manually adjust it.

Good luck. ;)

nelamvr6 27th November, 2002 02:31 AM

Quote:

Originally posted by CamoAlien
Rudzer - Hi. Impressive MHz count you have there. ;)
Thanks, but I'm not rudzer. :)

Quote:



Now, you have a very valid point about the Vcore. By all means, it should be able to reach 2.0 volts at the 2.0 volt setting. However, might it be possible that your board actually is functioning correctly, and is not failing to provide the correct voltage? Let me elaborate, using the electrical approach.

Given: You have an overclocked Athlon XP (T-bred core) 2400+ @ 2236 MHz.
You are running a very high FSB (most likely irrelevant)
You want the 2.0 volt setting to work
At the speed that your CPU is running, it is drawing a massive amount of current, and is producing a very large amount of heat (which is why they make giant heatsinks and water blocks and peltier chips).

Now, say you set it to 2.00 volts. However, it gives you 1.92 volts. This is exactly 4% under what it should be. Sure, 0.08 volts may seem like alot, but it is only 4% under.

Now think about this: you have a bunch of computers running, and all of the lights in the room are on. You pop something in the microwave, and the lights get a bit dimmer. Why does this happen? Voltage drop, and it happens when you are drawing a large amount of power (or a large number of amperes). Normal voltage for your standard wall socket in North America should be between 120 and 130 volts. Drawing a large amount of current could easily cause it to drop to between 110 and 115 volts (in other words, a 13% drop in voltage).

Similarly, at this speed, your CPU is drawing a large amount of power, and is causing a voltage drop. Those VRM's are doing their best to supply it with 2.00 volts, but they are putting out 1.92. The industry specifications for most electronics consider a 5% deviation as a low tolerance, and you are 4% below, which is within spec.

You have a point, and I admit it is possible that my PSU is not able to provide the current demand of it, but I'm not convinced that this is the problem.

My Enermax PSU is rated at 38A max and 43A peak on the 3.3 volt bus. One would think that that is sufficient. But to get more information I swapped in my Antec 430W PSU. Something interesting happened, the voltage topped off at the exact same 1.92V. The Antec PSU is rated at 28A on the 3.3V bus.

The fact that the voltage read the exact same at the top of the range leads me to suspect that the problem isn't the current source. I would expect that if the problem is that the Enermax isn't able to supply the current draw then the Antec would read even lower.

But you're right, it is still possible that the PSU is the problem. But I'm skeptical.

Quote:

...snip..
Anyhow, if you are seriously concerned about the voltage issue, it may be worth a look with a Fluke digital multimeter. You could also check the Vcore lines with an oscilliscope to watch for excessive ripple, which is another source of poor voltage regulation. Then, if necessary, either solder a varistor or use a clip-on wire on the IC which determines the Vcore (can't quote the IC # for you, haven't kept up on this one) and manually adjust it.

Good luck. ;)


No thanks! I've been down that road before!

And that's one reason why this situation is so vexing to me. I bought this board for a lot of reasons. I had plenty of KT400 boards to choose from. But I decided on this Epox board because the Vcore was supposed to be adjustable to 2.0V without modification.

But thanks for the input and the good luck wish!

I am as I mentioned enjoying some success. I believe that one reason is I am folding 100% of the time.

This has proven to be a great way to burn in the processor.

I started folding with my OC at 2247 MHz. At that time I was convinced that my system was stable because it would run Prime95 all night long without any errors.

But it wouldn't run the folding client for as much as an hour without problems! I was humbled! So I backed of my OC to 2210MHz. This was the highest freq that my system could run the folding client with no problems.

But after about a week of constant use I found that I was able to increase the freq to 2225. And now I’m at 2236 MHz and stable.

I believe that in time I will be able to reach 2247 again, and perhaps even higher.

Now if only I could get my hands on some more vcore... :)

CamoAlien 27th November, 2002 03:50 AM

Actually, I did not say anything about the power supply being too small. I'm sorry if I made it sound that way.

I was referring to the Voltage Regulators right on the motherboard (located near the CPU socket). I'm sure that they are very capable of handling the load, but they still could be a potential source. I haven't seen a picture of this particular board, so I have a question - are there heatsinks on the motherboards Voltage Regulators / how hot do they get?

Beleive it or not, I have built a few power supplies myself (not for computers - for testing purposes; 5 - 15 Vdc adjustable, 10A) and have had problems with voltage regulation and have had to troubleshoot the sources, so I do have some experience in this feild. :)

Anyhow, I'm sure that your power supply is plenty powerful. Both the Enermax and Antec supplies are great (I use an Enermax 550 watt myself - see sig). ;)

Quote:

Originally posted by nelamvr6

You have a point, and I admit it is possible that my PSU is not able to provide the current demand of it, but I'm not convinced that this is the problem.

My Enermax PSU is rated at 38A max and 43A peak on the 3.3 volt bus. One would think that that is sufficient. But to get more information I swapped in my Antec 430W PSU. Something interesting happened, the voltage topped off at the exact same 1.92V. The Antec PSU is rated at 28A on the 3.3V bus.

The fact that the voltage read the exact same at the top of the range leads me to suspect that the problem isn't the current source. I would expect that if the problem is that the Enermax isn't able to supply the current draw then the Antec would read even lower.

But you're right, it is still possible that the PSU is the problem. But I'm skeptical.


nelamvr6 27th November, 2002 04:19 AM

Yeah, I thought that's what you were thinking.

No heat sinks on the voltage regulators.

I hope its not the regulators, that would make it much more difficult to fix.

I'm still hopeful that it can be fixed by a BIOS update, but it won't be the end of the world if I have to live with it.

I'll probably be buying a new board in the next few months anyway.

Random Nonsense 27th November, 2002 12:38 PM

Quote:

Originally posted by nelamvr6


:confused:

Set my CPU to stock, overvolt it and see if that helps what? Are you suggesting that perhaps my increased FSB is somehow affecting the vcore voltage available? I find that very unlikely.


Voltage is essentiall "electrical pressure" correct?

Get a cylinder of gas. with a pressure guage, open up the valve a little. pressure slowly drops, whack it right the way open and it will drop off FAST add a compressor (or for electrics a PSU) now the valve only a bit open the pressure stays the same, a lot, it drops off. So, by keeping the stock settings you are opening the valve only a little. Heavy overclocking opens it a lot, your almost certain to get a small drop off if the PSU cant really cope. Also measure teh VCore with a multimeter. It may well be that it is being misreported as i stated before!


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