Ready to throw in the towel- my last (maybe) post on this

[Texun]

Just when I think I have a decent understanding of cooling I find something that befuddles me to no end. Temps on my XP2400 range from 47C idle to 50C loaded with a case temp average of 24C to 27C.

I'll get this out of the way now:
Started with this-
Mid-Tower Case
XP2400 - stock
ASUS A7V266C
MBM
SLK-800
80mm fan
Real ASIII
Vcore of 1.79,
Antec True Power 430 PSU \ Fan no more than about 3" from the HS
80mm Antec SF front and rear. The rear exhaust fan is no more than 2" from the top of the cpu fan and blows out.

What I've done since then-
Flashed the board with the latest BIOS - no change. Did it twice.
I've reapplied ASIII several times as per the instructions. Made sure the HS was not riding up on the socket.- no change
Tried fake AS once and the temps actually improved by about 3 degrees but still hit 50 unless the air cond is on.
Replaced the HS fan with a 92mm Antec SF- Quiet, but no temp change.
Lowered the Vcore to 1.69v - no change
I've tried various combinations of intake and exhaust fans - no change
Removed the side of the case. Still creeps up to 50C
Blown out what little dust there was- no change.

It seems that nothing I do will lower my temps. I know 50 is not bad but with what I have done I would expect to see a change somewhere. Case temps usually vary no more than 3 degrees with the side open or closed. To my knowledge they have never gone above 27C. Fans spin at around 2200RPM
BIOS shows the same temps +/- 1 degree.

This ASUS A7V266-C seems hell bent on running at near 50 no matter what I do. No crashes at all, but my goal (obsession) was to have this PC stay below 50C year round. It ain't happening! I've tried everything short of sacrificing a live chicken to break the temperature curse.

Any takers on this one?

 

[phokaz]

80mm fan on the SLK-800? What are the specs on it?

With an ambient temp of 80F, the tight space of that case with a 430w PSU in it, your vcore being higher then it should be, I would say your 116F-122F temps are about right.

2400+ 1.60v , If your running it stock, why do you need the vcore @ 1.79?

 

[Texun]

Originally posted by: phokaz
80mm fan on the SLK-800? What are the specs on it?

With an ambient temp of 80F, the tight space of that case with a 430w PSU in it, your vcore being higher then it should be, I would say your 116F-122F temps are about right.

2400+ 1.60v , If your running it stock, why do you need the vcore @ 1.79?

It is a little cozy in that case, but given the fact that my case temps range in the mid 20's I had expected better results from the HS, especially with the case open. As far as the specs on the 80mm fan, I have tried several.

The 80's that I used were Sunon TB2's which are 39CFMM at ~2900.
Antec's which are rated at 46 CFM at 2900rpm but I run them at ~2200.

I have an Antec on there as I type this. Case is open, temps are 27 case and 50 CPU.

I am going to try one other thing. I am going to hard wire the Smart Fan wide open and see if that helps. With my luck it will probably work great but drive me nuts.

About the 1.79 Vcore, the BIOS defaulted at that voltage. Had to move some jumpers to get it to 1.69v.

I would think that having the case open, using an intake and having the location of the 2" away from the HS would have helped.

BTW, I had an XP1700 Pal on here and had similar but slightly lower temps. Same set up.

Thanks for giving it a shot. Any other ideas??

 

[phokaz]

Make sure "Over voltage" is disabled.
Set vcore to the "1.7/1.675Volts" selection.

After that, theres not much else you can do other then getting some hardcore cooling going on. Its really a common problem with asus boards.

"To be able to monitor the thermal diode in the XP CPU, as well as monitor (somewhat) the temperature in the non-XP CPUs, ASUS put a transistor, wired as a linear diode (just like in the XP CPU) down in the CPU socket well, much like other companies put a thermistor. It is labeled Q90. To save money, they took the output from the pins in the socket which correspond to the internal thermal diode on an XP CPU and wired them in parallel with the thermal diode down in the socket well. Then they feed the combination into their ASIC for temperature monitoring. The greatest problem arises from the fact that since the diode down in the socket well is physically separated from the bottom of a non-XP CPU, it would read the temperature considerably lower than it actually was. So, in the computation that interprets the reading from the ASIC to where it is made available for Probe or MBM to read, they, in typical ASUS fashion, add something like 5-10C to the actual temperature. What results is that when you are using an XP CPU, the thermal diode inside read 5-10C higher than it actually is."

 

[Texun]

Originally posted by: phokaz
Make sure "Over voltage" is disabled.
Set vcore to the "1.7/1.675Volts" selection.

After that, theres not much else you can do other then getting some hardcore cooling going on. Its really a common problem with asus boards.

"To be able to monitor the thermal diode in the XP CPU, as well as monitor (somewhat) the temperature in the non-XP CPUs, ASUS put a transistor, wired as a linear diode (just like in the XP CPU) down in the CPU socket well, much like other companies put a thermistor. It is labeled Q90. To save money, they took the output from the pins in the socket which correspond to the internal thermal diode on an XP CPU and wired them in parallel with the thermal diode down in the socket well. Then they feed the combination into their ASIC for temperature monitoring. The greatest problem arises from the fact that since the diode down in the socket well is physically separated from the bottom of a non-XP CPU, it would read the temperature considerably lower than it actually was. So, in the computation that interprets the reading from the ASIC to where it is made available for Probe or MBM to read, they, in typical ASUS fashion, add something like 5-10C to the actual temperature. What results is that when you are using an XP CPU, the thermal diode inside read 5-10C higher than it actually is."

At last! My suspicions are confirmed. I had heard somewhere before that ASUS boards showed temps averaging 10 degrees higher than some other boards but I could never find an explanation to confirm this. Now I have a better understanding of the problem and the logic behind it.

BTW, I hard wired a 92mm Smart Fan to full speed (2400RPM) and the temps are still in the upper 40's C but I haven't had it running like this for very long. It may hit 50 or it may not. I think the best thing for me to do is dump MBM so I don't see the temps.

Also, the 92mm fan is not too bad at full RPM. I suppose the larger surface area of the fan blades help in that respect. I've read that the hub diameter on 92mm fans blocks some of the air but I held it up next to one of the many 80mm fans that I have and in some cases it is actually smaller.

46C and holding. I can certainly live with that, and especially so now that I have read an explanation of the ASUS temp sensor problem. It's getting late here so I'll give it a better check tomorrow.

Yes folks, this is a sickness. I set a goal a long time ago to have a fairly quiet system that would perform well and still run cool. This is not a necessity but more of a nagging nuisance that I have been fighting with for a long time.

Thanks, and I appreciate the help!

 

[brucehao]

Very interesting... does this "inaccuracy" pertain to Pentium chips as well, specifically P4's???

 

[cheapgoose]

as far as I know, onlt the asus a7v333 reports temp using thermal diode. anyway, your temps are bad at all. my 2400xp with sk7 and 52 cfm fan was getting almost 60 C. of course my case has no circulation right now.

 

[Texun]

Originally posted by: cheapgoose
as far as I know, onlt the asus a7v333 reports temp using thermal diode. anyway, your temps are bad at all. my 2400xp with sk7 and 52 cfm fan was getting almost 60 C. of course my case has no circulation right now.

Thanks. Given the amount of traffic generated in cooling forums I would have expected to read or see more detailed info about this subject. Most of what I have read on this has usually consisted of little more than a one line blurb about ASUS mo-bo's reporting or running higher than other boards. I've never found much detail on the subject.

 

[mechBgon]

Originally posted by: texun

Originally posted by: cheapgoose
as far as I know, onlt the asus a7v333 reports temp using thermal diode. anyway, your temps are bad at all. my 2400xp with sk7 and 52 cfm fan was getting almost 60 C. of course my case has no circulation right now.

Thanks. Given the amount of traffic generated in cooling forums I would have expected to read or see more detailed info about this subject. Most of what I have read on this has usually consisted of little more than a one line blurb about ASUS mo-bo's reporting or running higher than other boards. I've never found much detail on the subject.

Here's more info than you can shake a stick at, as far as the A7V333 goes. Like virtually all recent AMD boards, it watches the CPU's internal diode for overheat... but like virtually all recent AMD boards, it keeps the reading to itself and gives you an estimated reading from a thermistor mounted on the motherboard's surface, inside the socket cavity. MBM5 can steal a reading from the internal diode for you, but the calibration took a huge dive around the 1012 BIOS or so

The boards that really do give from-the-core live readings without resorting to MBM5 tricks: EPoX 8K3A's and Gigabyte 7VRX's (revision 2 only).