K6-III+: New AGP Card = CPU hotter

Discussion relating to Socket 7 hardware.
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carlcoconut
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K6-III+: New AGP Card = CPU hotter

Post by carlcoconut »

Hi there,

so here's my very first post on k6plus. I am reading here for quite a while now, but now I need some help...

I recently upgraded lots of my hardware.
I'm now running a DFI K6BV3+/66 with 2MB Cache.
Also I got hold of a K6-III+/400. I let this run at 550Mhz at 2,2v.
I used to have a Matrox Millenium G200 AGP Card in it and everything ran very well. CPU Temperature was at about 33° Celsius (according to Sandra and CpuCool)
Now I wanted to change my AGP to either Elsa Gladiac 511 (Geforce MX 400) or Voodoo 3500.
So here start the problems. With both cards I get an alarm from the Motherboard Monitor, that the 12V Voltage is too high. I disabled the monitoring and booted into XP. With CPUCool I get a 12V Voltage of up to 13,37V with the Elsa Gladiac .
Also I notice an increase of the CPU Temerature. It now is about 6°-15° Celsius higher than before.
With the Voodoo 3500 it was even worse: Even higher voltages and CPU Temperatures sometimes over 50°.

Can anybody tell me, why these AGP Cards change the Voltages on the motherboard? Is my 300W Power supply too weak?

And why is the CPU temperature rising? Is it because the Vcore also rises?

thanks for any info
Carl


-------------------------------------------------------------------------------------
AMD K6III+ 400 @ 550 2.2v w/Alpha 6035
DFI K6BV3+/66 Rev B+ 2 MB Cache
728 MB PC133
Elsa Gladiac 511/TVOut 64MB (Geforce 400 MX)
Promise Ultra66 Controller
4 IDE Harddisks...
georgep1
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Re: odd temps

Post by georgep1 »

Very strange symptoms indeed. My first guess would be a faulty power supply. A good working 300W PS should be more than enough for your system, powerwise.

At first I thought some of the temperature increase could be from the video cards producing more heat than the Matrox one (the V3 3500 is really hot), but the GF2 MX is not a hot running card.

Another, more problematic possibility is that the motherboard suddenly had some failure in the voltage regulators. I don't know how you would test that though.
E-Machines T6000 (AMD64 3200+) (Don't laugh! It absolutely rocks!)
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carlcoconut
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Re: odd temps

Post by carlcoconut »

georgep1 wrote:Another, more problematic possibility is that the motherboard suddenly had some failure in the voltage regulators. I don't know how you would test that though.
When I change back to the Matrox G200 then everything is OK again. So my voltage regulators should be OK, shouldn't they?
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Post by cake »

You don't happen to have a spare PSU to try with?
Just to rule out a faulty PSU..
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Post by Guest »

Are the temperatures you're giving from when you are running things or the system is idle?

If you have a faster video card and are running applications that are demanding on it, you *should* get higher CPU temperatures since the CPU is doing more work. If it's waiting on the graphics card a lot, it's going to have a lower temperature.

I would check my CPU utilization and see if it's higher. If it is, particularly with floating point, it will get hotter. If it's not, it's probably something else.

It's a longshot, but it might explain why your CPU temperature is higher. Of course, a higher ambient temperature in the case could also be the problem, so you'll want to check that out too.
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punkrawker82
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Post by punkrawker82 »

Have you tried running the K6-III at stock speed and voltage with the new Videocards?? Say for instance 400mhz at 2.0v...
Then from there work your way up to as fast as it'll handle...It might not be 550mhz with 2.2v, but it'll be more stable and possibly still overclocked...though not as much.

Also...

Have you tried newer cards like a GeForce 4 MX 420-460?? I think the newer the card the less voltage it sucks. There is probably a huge difference between the first generation GeForce cards and 3DFX cards compared to a new GeForce 4 or Raedon. Its like the original K6 CPU's needing more voltage than a K6-2/III/+ because they use a bigger die process or whatever...


Experiment with CPU settings and a not so old videocard if there's one available... :D
Past System
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Asus P5A-B rev1.05(Beta BIOS 1011.005)
AMD K6-2/CXT AFX @ 500Mhz(CPUCool 5 x 100)
128Mb PC100 SDRAM
VisionTek GeForce 4 MX 440 4x AGP @2x w/ 64Mb DDR
Creative Ensoniq PCI Sound Card
ADS Turbo Quad 4 Port USB PCI Card
Linksys NC100 v2 NIC
Western Digital 8Mb Cache SE 80Gb HD
Lite-On 52x32x52 CDR/RW
Lite-On 16x48 DVD

Current
----------
Athlon XP-A(Barton) 2600+ @ 1.91Ghz
Abit NF7-S v2.0
512Mb Kingston 3200 DDR(2.5-3-3-7)
VisionTek GeForce 4 MX 440 4x AGP w/ 64Mb DDR
carlcoconut
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Post by carlcoconut »

Anonymous wrote:Are the temperatures you're giving from when you are running things or the system is idle?
Even right after bootup in the BIOS page the temperature is already that high and the 12V alarm sounds.
I think I have to measure the voltages myself and see if I can trust the health monitor.
I just read about the voltage problem/oddity with this board on older usenet postings. It seems that nobody ever really solved this.

By the way, what is the normal temperature of a K6-III+/400 running at 550?

I didn't try a newer video card, just the old Matrox G200.
Also another PSU isn't available to me at the moment, but I don't think that this is the problem as everything is normal using the Matrox...
carlcoconut
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Problem solved!

Post by carlcoconut »

OK, I took a voltmeter home from work and measured the voltages.
Everything looks fine. I get nice 5.04V and 12.38V while the monitor says 5.18V and 13.29V.
So I assume that the CPU temperature is also some percent lower...
Facit: Never trust your motherboard sensors...

thanks for your suggestions.
Carl
TA152H
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Post by TA152H »

Carl,

I have a K6-III+ ACZ 400 on this machine, with a FoxConn heatsink that I got from Ebay for around $12 that works so well I do not even use the fan. It is overclocked to 550 MHz and runs with 2.0v and still never gets hot even running Dungeon Siege which absolutely eats up the processor. It runs pegged the entire time, and while the heat sink gets warm, it never gets hot. I will check temperature after I reboot and post it. The BIOS on this motherboard is screwy, it misrepresents the temperatures. The case temperature is actually the processor temperature, and the processor temperature is the case temperature. Consequently I can not read it with a utility that shows the processor temperature.

If you can not go "topless" with your processor, I would say that dropping down to 500 MHz and the corresponding voltage should do the trick (Mine runs at 450 with 1.6v, 500 with 1.8v, and 550 with 2.0v). The loss of speed is barely perceptible, but it is very quiet and uses less energy to boot. So, all in all, it may be worth it to you unless you need every last CPU cycle. But then again, maybe a newer processor is in order if this is the case.
TA152H
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Post by TA152H »

Just an FYI on a very simple test I ran.

I tested a K6-III+ at 450 MHz with voltages of 2.0v and 1.6v, with just a heatsink (no fan) on it to see how much voltage changes matter when running at the same speed. In short, they do.

At 2.0v, it ran at 55 degrees Celsius. When I put the fan on, it dropped all the way down to 35 degrees in a relatively short period of time. At 1.6v the processor ran at only 41 degrees at the same clock speed, so the change the pretty dramatic. I then declocked it further, running it at 400 MHz and 1.6v, which only dropped the temperature to 39 degrees.

Typically I would run the machine at 450 MHz and leave the voltage at 2.0v so if I wanted to I could bring it up to 550 MHz without having to reboot or open the case. After this, I dropped the voltage down since it makes so big of a difference in temperature and I rarely need it at 550 MHz anyway (Dungeon Siege is all I use it for).

I thought some of you might find this as interesting as I did.
carlcoconut
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Post by carlcoconut »

Thanks very much for your interesting research.
In fact I used 2.2v just to try to get the K6-III+ to run at more than 550Mhz, but with no success. I can also run it at lower voltages (2.0v at 550Mhz should do), I just was too lazy to change it back.
I'm using one of those low power "embedded" K6-IIIE+ processors that are labeled 400Mhz/1.6v Core. In fact these are exactly the same as the non-embedded ones. If you carefully read the AMD-K6-IIIE+ Embedded Processor Datasheet (http://www.amd.com/epd/processors/6.32b ... 23543a.pdf) then you'll see no real difference* to the datasheet of the older K6-III+ (http://www.amd.com/us-en/assets/content ... /23535.pdf). Very interesting is the fact that the Absolute Ratings for all these so called embedded processors are the same: Maximum Core Supply Voltage: 2.2v. Also note that the maximum temperature before long-term reliability is affected can be amazing 110 degrees Celsius.
I think just for fun I'll try one of my other seven K6-IIIE+s if it can reach more than 550Mhz before I sell some of them...

*The only difference seems to be the fact that the K6-IIIE+ in the standard 2.0v version doesn't support the PowerNow! function which I don't believe to be true...
TA152H
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Post by TA152H »

Carl,

I have 3 K6-III+ ATZ (400 MHz, 1.6v) processors and I could not get them to run reliably at 600 MHz no matter what I did (which included prayers to all the known gods). I got one to POST, but it sort of went south after that.

I have 1 K6-III+ APZ (450 Mhz, 1.7v) that would post at 2.0v and boot a little ways in. At 2.1v it got further and almost loaded Windows entirely. At 2.2v it was rock solid for about 3 hours pegged (after that I took it out again; I was just testing it).

Not sure if it just coincidence or if the APZs come from a better part of the wafer.
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