Uhhhhh...X1600 in iMac horribly underclocked?

Discussion in 'Windows, Linux & Others on the Mac' started by Alexander, Apr 6, 2006.

  1. macrumors member

    Joined:
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    #1
    I just ran ATITool 0.25 Beta 14, and it showed that the X1600 in my low-end iMac was running at 313MHz core, 300MHz memory.

    So I overclocked it. It's now stable at (no typo) 440MHz core, 576MHz memory. Yes, that is about 50% faster, and FPS readings back that up.

    Keep in mind that the Mobility X1600 is supposed to be clocked around 470MHz core, 470MHz memory. The desktop version of the chip is the same, but is clocked about 100MHz+ faster.

    It should be able to be pushed even faster when we actually have the fans running properly.
     
  2. macrumors 6502a

    jamesmcd

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    #2
    I was starting to wonder actually... BF2 was giving me pretty bad FPS. How did you overclock it?
     
  3. macrumors 68030

    BlizzardBomb

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  4. Moderator emeritus

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    #4
    That's a lot but don't you worry about overheating? I think the reason they went with the nVidia chipset originally was because it didn't produce a lot of heat.
     
  5. macrumors 65816

    Josh396

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    #5
    Wow. I guess the good news about it being underclocked is the performance I'm getting out of it. I've been extremely impressed with the card. However, if I'm able to get better performance out of it I'd love to. How did you go about overclocking it? Also, how big of improvements in FPS did you see and in what game? Thanks a lot.
     
  6. macrumors 68020

    R.Youden

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    Apr 1, 2005
    #6
    I think this may be quite common with Apple hardware, it maybe one of the reasons why the OS is more reliable. It would be interesting to see what happens in the long run. Do any of you board temps increase dramatically with this overclocking?
     
  7. macrumors 6502a

    jamesmcd

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    #7
    That link that was provided earlier is to a mac o/c tool. We are after the XP version I should think.
     
  8. thread starter macrumors member

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    #8
    Here's the link:

    http://www.techpowerup.com/downloads/259

    Just download, install, then hit the Find Max Core/Find Max Mem buttons, and give it a while.

    Keep in mind that BF2 is a real RAM hog, I wouldn't try playing it with less than 1GB, and 2GB is better.
     
  9. macrumors 65816

    Josh396

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    #9
    Looks like a good program. However, when I dual boot into Windows would it how would it preform? I would assume everything would be okay, but is there a greater chance that something could go wrong if I'm playing CS:S?
     
  10. macrumors 6502a

    jamesmcd

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    #10
    Cheers for that. This doesn't flash the card at all does it?
     
  11. thread starter macrumors member

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    #11
    No. Overclocking does not increase heat output, unless you start increasing the voltage, which I don't even think you can do without some hardware hacking.

    For any given temperature, there is a speed that will be reliable. The reason overclocking exists is that for the max temperature your system is likely to see, that reliable speed is much higher than the speed that the manufacturer decided to run the chip at.

    The X1600 in my iMac is clearly FAR underclocked. I was able to push it to 445/585 before it started glitching. Pull it back a few MHz, and voila, stable system.

    If, for some reason, my machine ends up running hotter one day (summer?), it may start randomly rebooting, showing graphical artifacts, etc. I will know to decrease the overclocking a little bit at that time.

    Alternatively, I could pull the overclocking FAR back from the maximum I observed, to, say, 400/500, and I guarantee you I would never see a problem.
     
  12. macrumors 6502a

    Steve1496

    Joined:
    Apr 21, 2004
    #12
    Yeah, I was just running ATITool too, it can really improve performance. I clocked my core at 440 as well, memmory 540. My iMac was at 380 Core, 320 memmory by default.

    In 3D View, it's now showing the 3D effect at 104FPS average!


    Steve
     
  13. thread starter macrumors member

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    #13
    No, it's a setting that is automatically reset on reboot. (which is why an OS X overclocker would be useless for XP.) You can set the software to automatically launch and fix the clock speeds on each startup, if you like.
     
  14. macrumors 65816

    Josh396

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    #14
    I have 2 GB of RAM so I'm okay there. I see the program you linked is a windows program (that or I can't read correctly), have you ran any games on OS X to see if theres improvement there? Or is it just windows specific? Also, (probably a stupid question) could it be possible the drivers made by Apple for Windows affect it somehow? Could they have underclocked it for Windows only? Thanks again.
     
  15. macrumors 6502a

    Steve1496

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    #15
    Just be careful how far you go. I just got this after it froze for about 15 seconds.
     

    Attached Files:

  16. thread starter macrumors member

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    #16
    Yeah, that kind of error is normal after you hit the ceiling. Clearly you'll want to run it a little slower than the speed that caused that. ;)
     
  17. macrumors 68040

    Kingsly

    #17
    What are the clock speeds on the MBP?
    What kind of FPS are you getting now that its overclocked? Before you overclocked?
     
  18. Moderator emeritus

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    #18
    Well, it definitely seems reasonable. I'd like to see it work similarly in the MacBook Pro. Apple generally likes to play it safe. It's good to see that it's possible to go much further.
     
  19. thread starter macrumors member

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    #19
    Test scene in Guild Wars was about 30FPS before, about 47FPS after.

    I'd be curious to know about default speed and overclock potential of the MBP as well. You should be able to get into a similar ballpark, since it's the same chip. It's probably cooled differently in the MBP, though.
     
  20. macrumors 68030

    BlizzardBomb

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    #20
    Just to make sure you guys are aware, this voids your AppleCare.
     
  21. macrumors G4

    Lord Blackadder

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    #21
    I disagree - In my experience with a Radeon 7500, 9600 Pro and GeForce 6800GT overclocking can cause temperatures to jump by as much as 20C. For example, when running my GeForce 6800GT at the "stock" speed of 350/1000MHz the card idled around 58-62C, which is warm but not unusual for this card. An overclock to 400/1100MHz produced idle temps of up to 80C, which is a little too hot for daily use without an upgrade to the heatsink-fan setup. Higher average temps = shorter video card lifespan.

    Running overclocked day-to-day at hihger temps is less of a concern when you are running a regular desktop video card, but if by some mischance you burn up the GPU in your iMac you're screwed.

    I'm not saying don't OC your video cards, just be aware that the risk is substantially higher in Macs with non-upgradable video cards (i.e. all Macs other than the towers). If any of you choose to fiddle with overclocking, make sure to download the Temperature Monitor app from versiontracker and be aware of what your GPU's shutdown temp is - you'll want to stay WELL below that (by perhaps at least 30%) at all times.

    IIRC, the X1600 in the iMac is a mobility GPU, so it should be rated for a lower clock than the desktop version. Also, I'm not sure what kind of thermal management the GPU in the iMac gets, so Apple may have cranked the speed down a notch for reliability reasons.

    Those claimed FPS improvements are pretty good though - as long as the OC is truly stable it may be something for the gaming enthusiast iMac owner to consider.
     
  22. macrumors 68020

    daveL

    Joined:
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    Location:
    Montana
    #22
    That's Just Plain Wrong

    I'm sorry, but there's no way a chip is going to run at a higher clock frequency and not produce more heat. Think about the physics of it for a moment.
     
  23. thread starter macrumors member

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    #23
    Hehe, you got me, I was just makin' stuff up.

    So, does hacking in a water-cooling system void my AppleCare too?
     
  24. macrumors 68020

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    Mar 30, 2004
    #24
    Yeah, don't try unless you know what you're doing. Or start saving for a new logic board!
     
  25. macrumors 6502a

    Steve1496

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    #25

    I would say I know what I'm doing, but I wanted to try things out. Live dangerously:)


    Steve
     

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