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CPU prob or video? Stable at max with one card. Unstable with other.

By Mugsy
Jun 30, 2005
  1. This is totally bizarre. I've been working on this problem for weeks now. Hopefully someone can help.

    I have an authentic AMD XP 3200+ processor and ATI Radeon 9800 Pro vid card (using DVI output on an LCD). Sometimes after about an hour or so of use, the computer will crash. Originally, I was experiencing three different types of crashes, but I traced one of them back to CPU overheating. Adding a case fan and larger fan on the (all copper) heatsink "appears" to have solved that one. However...

    Sometimes the video will just futz up (black screen with garbage on one side) for no reason. The problem got so bad after a while, I removed the 9800 and re-inserted my old nVidia 440 MX (a $28 card). Still at 3200+, the crashes went away, but the quality on my LCD was so bad, I couldn't stand it anymore and put the ATI back in. The crashing resumed.

    I then discovered that by setting my 3200+ to "2500+" in the BIOS, the crashing stopped. Weird. Why would changing the CPU speed make the video more stable??? And what can I do about this?

    Please help. I didn't spend the extra money on a 3200+ just to run it at 2500+. puke:
     
  2. zephead

    zephead TechSpot Paladin Posts: 1,569

    run cpu-z to verify your cpu's actual clock speeds. btw, what motherboard?
     
  3. Mugsy

    Mugsy TS Guru Topic Starter Posts: 361   +9

    More info.

    Thanks for the reply Zep.

    I have several CPU-ID programs that all identify it as an "AuthenticAMD", Model 10, Barton Core Athlon XP clocked a 2198MHz (the normal speed for a 3200+). I am using a Soyo Dragon Ultra Platnum with VIA KT600 chipset (fan on chipset). Not the fastest board in the world I'm sure, but loaded to the hilt with RAID, 2 Firewire and 6 USB2 ports, SATA and a 6-in-1 Memory Card reader, all for just $99.

    I run the computer with the side off and a small deskfan blowing on the capacitors at the rear of the PCB (pointing it straight in puts drag on the CPU fan and makes things worse). I also started using "CPU Idle" to help cool things down (and to my surprise, it actually does work), but these things alone do not solve the problem. Only underclocking the CPU one step from 3200+ to 2500+, or installing a cheaper/slower vid-card, stabilized the computer.

    This is what has/had me thinking it's a "cooling" problem.

    Yesterday, I installed "PowerStrip", the video card tweaking software, and tried "underclocking" my Radeon by 15%. Using these two programs (Idle and Strip) dropped my average CPU temp by almost 8'C!!! and (so far) hasn't crashed. (A MUCH better solution than running the whole PC slower or going back to using a $28 VGA card!)

    I guess I'll need to put a GPU cooler on the card if I want to run it at full speed, but the only guess I can make as to why running the Radeon at full speed would increase the CPU temperature is that the heat from the card was increasing "overall" temperatures and causing the crashes. Underclocking the card helped cool everything down and I'm able to run stable at 3200+ again.

    I'm thrilled... puzzled... but thrilled. Bizarre. Thanks.

    :hotbounce
     
  4. zephead

    zephead TechSpot Paladin Posts: 1,569

    i'm glad you found a workaround. in the future, should more complications arise, try swapping motherboards with a better one that is known to work good. if you haven't got the parts, a local pc repair shop would test it for you, costing less than $30 (USD)
     
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