Trouble with 7800GTX

Discussion in 'RivaTuner Advanced Discussion forum' started by JuanFlaiter, Jun 23, 2005.

  1. JuanFlaiter

    JuanFlaiter New Member

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    GPU:
    2x7800GTX E.S.
    Hi guys,

    I have huge performance drops overclocking with Rivatuner with a couple of 7800GTX.


    With Coolbits I have no problems, but the internal test sux, I prefer Rivatuner because you can bypass.

    Any thoughts about this? If this is being fixed when are you publishing the new release of Rivatuner?

    I'm a huge fan of this oc utility.

    Greets from Chile!
     
  2. michealace82

    michealace82 Master Guru

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    GPU:
    2 X BFG GTX 285 OCE 1GB
  3. Unwinder

    Unwinder Ancient Guru Staff Member

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    Don't feel offenc, but I have to repeat it once agian for users _purposely_disabling_ stress testing and setting the clocks _beyond_stable_ ones, then claiming that such overclocking causes throttling: always think what exactly are you doing. You see that the driver detected some troubles during stress-testing these clocks. You see that it treats these clocks as unstable (i.e. there _were_ some errors in GPU's functionality during performing stress tess). You see that, but still force it to run at these clocks. You know that as soon as the driver will detect similar error during running any 3D application, it will throttle clocks down. You know that the chip may simply periodically hang on these clocks (happily there is RobustChannels technology in the driver, allowing to reset chip dynamically after hang). You know that but still go beyond safe limits.
    Then you come here, claim that there is performance drop after such "overclocking" and ask me to fix that in the next release of RivaTuner. Where is the logic? And what exactly can I fix? ;)
     
  4. JuanFlaiter

    JuanFlaiter New Member

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    GPU:
    2x7800GTX E.S.
    Sampsa and Shamino both 3DMark WR had the same problem and in past versions haven't had it. All the top scores in 3DMark had at least a pair of artifacts. I'm not seeing artifacts and my temperatures are ok, I just thought a pair of clocks more would be great for testing purpose.

    If I where into safe limits I wouldn't overclock. If I where into safe limits they wouldn't give me this cards for testing. If I where into safe limits computers wouldn't be fun for me and would be playing golf.

    I was justing asking if someone else had this performance drops, maybe it had something to do with RT, but as I see you just like positive feedback:

    Your utility is really great, it has helped me a lot and I've recommended it to all my friends.

    Thanx!
     

  5. Unwinder

    Unwinder Ancient Guru Staff Member

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    It is not a question of liking/disliking positive/negative feedback. If there are real troubles in RT, I'm always open foir fixing it. It is a question of absolutely illogical problem reports, posted by some users. I cannot fix errors in user's logic, but I can prevent other users from using such logic and posting similar "problem reports".
    Your just overclocking too far. If you doesn't see any rendering anomalities, it doesn't mean that the card is pretty stable on the clocks you're setting. The driver never throttles down just for fun, there are a lot of things like chip undervoltage limiting max stable clocks.
     
  6. Sampsa

    Sampsa New Member

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    I've now specially modified BIOS from NVIDIA which removed this performance drop when using "disable internal test" with Rivatuner.

    In this case GeForce 7800 GTX started it´s thermal throttling when temperature of the card dropped below 35C and when clockspeeds were raised above 525/1380.

    Maybe in the future Unwinder can take a look at this BIOS and try to apply this mechanism to Rivatuner (if possible).

    Unwinder, you can check out my results with 6800 Ultra and LN2 here: http://www.muropaketti.com/3dmark I'm very well aware how does the system/graphics cards work under extreme cooling and high clock frequencies :)

    PS. NVIDIA recommends using Rivatuner for 7800 GTX overclocking :)
     
  7. Unwinder

    Unwinder Ancient Guru Staff Member

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    Hi Kurri,

    Don't mix thermal throttling caused by too low temperatures (so called "cold bug") and throttling caused by RobustChannels errors (i.e. throttling due to chip instability caused by too high clocks). That's absolutely different things. The second one cannot be "fixed" by anything but core voltage boost. The first one is a natural driver/BIOS bug (there is a thread about this cold bug in this forum, where I've explained technical background of this problem in details) and it really can be fixed by BIOS (I also see no reasons, preventing NV from implementing similar fix at NVIDIA driver level in future). But if you'll follow our "cold bug" thread, you'll find that it is impossible to fix it at any third party util level. The fix (i.e. sensor's lower Tcritical limit) must be applied _before_ the driver start and receive ALARM report from the sensor via GPIO pins.
     

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