GPUs, a G4DA and heat-related crashes

Discussion in 'PowerPC Macs' started by ziggy29, Mar 25, 2017.

  1. ziggy29, Mar 25, 2017
    Last edited: Apr 4, 2017

    ziggy29 macrumors 6502

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    #1
    So I've been messing around with my G4DA again (upgraded circa 2007 with an OWC CPU, 1.467 GHz).

    The beast I am trying to tame is heat. I have four AGP GPU cards for this machine I can swap in and out. The stock GeForce 2MX works fine, as does a 4MX upgrade I acquired a couple years ago. These cards seem to have no heat-related instability.

    I also have a 4Ti 4600 and a FireGL X3 (the latter appropriately taped) and they both scream on this machine.... but I can not run them for more than a few minutes without crashing or freezing with the Mac's side door closed. When I open that door wide open, both cards are very stable and can run for hours on end doing fairly intensive stuff. That tells me that with 99.9% certainty the culprit is heat.

    It's not just that these other two cards generate more heat but also that their form factor prevents sufficient air flow when the door is closed. I'd love to be able to use one of these two as my regular "go to" GPU on this machine but the heat issue makes me shelve them most of the time and stick with the 4MX (at least I can use DVI output with it, as opposed to the 2MX).

    I'm interested to hear any (hopefully not too draconian or expensive) suggestions y'all may have with respect to heat and airflow in this machine. I'm willing to concede the X800 may never work with the door closed, but I'd like to think the 4Ti could be made to be stable.
     
  2. eyoungren macrumors P6

    eyoungren

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    #2
    Adding extra fans is about all you can do. You may want to replace the 120mm exhaust fan as well.

    Find the largest CFM fans you can. The brands I used on my QS were bBlaster and Cooler Master.

    That said, everything prior to the MDD is just a poor design thermally. That giant exhaust fan has to make a 90º bend to exhaust hot air. Just don't know what Apple was thinking.

    I knocked a hole in the bottom of my QS and put in an extra 120mm fan and removed the speaker and mounted a 80mm fan there. So, my case had two intake fans and two exhaust fans.

    That's extreme and not what you are looking for, but I'd at least start with replacing the main exhaust fan.
     
  3. Eriamjh1138@DAN macrumors 6502

    Eriamjh1138@DAN

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    #3
    This is why Apple put port holes on the MDD model: For more airflow.

    All previous designs more or less suck air in from the bottom and gaps in the side panels. Put a big enough fan inside and the case would probably whistle or scream like a high-pressure air leak on the space shuttle.

    Have you tried redoing the heatsink compound on the video card? If it's dried and not efficient, it will not transfer heat as well as new compound might. It might help a little.

    Here's another idea: A pair of slot fans around the card. Wire one to bring air in, the other to push air out. Put one on each side of the video card. It's a long shot.
     
  4. ziggy29, Mar 26, 2017
    Last edited: Mar 26, 2017

    ziggy29 thread starter macrumors 6502

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    #4
    Thanks. They were probably thinking people weren't going to put fire-breathing GPUs into them. :)

    I may do a little of bit of fudging around, but I may also decide that the 4MX may have to do in terms of being the regular "go to" card for this machine; it is certainly more than adequate for most of what I do.

    Is the main exhaust fan 120x25? Or would 120x38 fit (as the latter seem to be available with up to 150 CFM as far as I've seen)? Of course, the ones with the greatest CFM probably sound like an aircraft taking off, but I guess you can't have very quiet and very powerful. I wonder what the stock fan is rated for. I'm seeing some 120x25s in the neighborhood of 90 CFM.

    I am also assuming that "new" fans probably have different connections than one that would work with the old G4 towers.
     
  5. ziggy29 thread starter macrumors 6502

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    #5
    OK, I've gone into the case, removed the fan (except for where it connects to the PS). I'm not sure how to disconnect the cable; I feel like I'll break it if I try any more without knowing what I'm doing (picture enclosed). Is there something I need to push on while simultaneously pulling, or something like that? They certainly don't just seem to come apart when you pull on the connection. It's also a good opportunity to give that area a good cleaning.

    It seems like that tab-like thing on the right side has something to do with disconnecting? I've messed with it as much as I dare, but can't get this connection apart.

    G4FanConnector.jpg

    The stock fan is a "Sensflow WFC1212B". I haven't found any specs on this one so I don't know what kind of CFM it moves. Also need to put a can (or two) of compressed air on my shopping list.
     
  6. eyoungren macrumors P6

    eyoungren

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    #6
    You press down on that little tab and then pull. It slides out. The QS has the same connector.

    As far as fan size, it's the standard 120mm case fan. Never checked the width but anything larger than the standard won't fit.

    The Cooler Blaster I used was 90cfm I think. I had a bBlaster later on that did something around 100.

    As far as more modern connectors, just use whatever comes with the new fan to hook it up to a spare Molex cable and run the fan from that.
     
  7. ziggy29 thread starter macrumors 6502

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    #7
    Yeah, was just going to report that I managed to pull it apart. And you just answered my next question (about using Molex), since I figured this probably had an obsolete type of connection. I do have two unused Molex connections in here, so it's good to know that as long as I get a fan that can get its power through Molex (or can easily get an adapter for it), I should be good to go with a standard 120x120x25. Molex adapters are common and cheap.
     
  8. eyoungren macrumors P6

    eyoungren

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    #8
    Yep, most of the reputable fan manufacturers include adapters with their product such as a two prong to Molex adapter in the box. So, don't limit yourself if you find a good fan. Places that sell them also should have adapters as well so you should be covered both ways.
     
  9. ziggy29 thread starter macrumors 6502

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    #9
    The general consensus I got on the width is that while a 38mm-wide fan will generate more CFM and will fit, it also leaves little to no room between the back of the fan and the side of the case, leaving almost no place for that extra airflow to go -- so better to stick to 25mm fans.
     
  10. ziggy29 thread starter macrumors 6502

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    #10
    While not intended to be a long term solution, I bought a cheap Chinese fan, 120x120x25, claiming to do about 120 CFM. (It had a 3-pin connection and I used a 3-pin to Molex to power it.) I installed it and ran it just long enough to make sure it works today; I should have time to really test it tomorrow. I can say it moves a LOT more air than the stock fan.... also it is VERY loud. But this will give me at least some idea whether just a stronger fan is feasible. (I also have three unused PCI slots next to the GPU and I removed the backplates for those three slots. I feel a lot of warm air moving through them and out the back with this fan, and felt almost none with the stock fan. Would like to be able to bring in more outside air with another fan, but short of major surgery, I don't think that's possible with a DA.
     
  11. eyoungren macrumors P6

    eyoungren

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    #11
    If you're brave enough, you can also replace the stock PSU fan. It's an 80mm fan.

    The one I replaced mine with was a bGears b-Blaster. Moves 62CFM.

    35-132-020-02.jpg
     
  12. RhianB, Apr 4, 2017
    Last edited: Apr 4, 2017

    RhianB macrumors 6502

    RhianB

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    #12
    In regards to the FireGL X800, I would start with an exhaust fan in the PCI slot below the GPU. The GPU exhaust fan pulls air through the GPU heatsink, so the PCI slot exhaust fan below it captures this hot air and pushes it out the back of the case. A setup like this:
    Fan2.jpg
    You can pay up for the adjustable x2 exhaust fans or go with a single. If it were me, I think I would try something like the one below as the doubles do a great job of pulling air but IME a poor job of actual exhaust. They instead rely on a solid exhaust system already in place.
    s-l300.jpg
    http://www.ebay.com/itm/Antec-Super...415723?hash=item5b26b4eeab:g:VgkAAOSwGIRXbF21

    I also like the variable 3-way speed control switch on the back. Anyhow, there's a lot of options on ebay that hit multiple price points. Good luck.
     
  13. ziggy29, Apr 6, 2017
    Last edited: Apr 6, 2017

    ziggy29 thread starter macrumors 6502

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    #13
    I'm considering something like that double fan you show above, especially if it's a lot more quiet. Though part of me is wondering if the more "passive" cooling of leaving the slots empty and blowing the air through the back of those empty slots might be good enough, or maybe even more effective.

    I'm putting this computer through the motions now, and after more than a half hour with the FireGL card and the door closed it's still stable and running. A lot of warm air is coming out of the back, with the air being forced out the back through the holes left by removing the backplates of the three unused PCI slots. I have four PCI slots; the one farthest from the GPU has a USB 2.0 card in it. Then there are three empty PCI slots, then the GPU. But my goodness, is this fan ever loud!
     
  14. eyoungren macrumors P6

    eyoungren

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    #14
    Maybe we have to define loud. :)

    At one point I had the PSU fan (80mm), case fan (120mm) the bottom fan (120mm) the intake fan (60mm) and a 80mm fan mounted at the speaker hole (I removed the speaker) hooked up and running. Including the dual CPU fans, the noise never bothered me even though I knew it was louder than stock.

    Now, a G5 with fans on full blast is loud to me and my poor old QS never approached that.

    Perhaps it's because I've lived with fans as background noise since I was 10…
     
  15. ziggy29 thread starter macrumors 6502

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    #15
    Well, it's the loudest computer fan I've ever heard, though I've never heard your QS (or a G5, for that matter).

    This is the one I picked up. It certainly does move a lot of air. Two hours of steady use now, and no crashes, no freezes, no beachballs (no more than usual with the side door open). I've played full screen MP4 video using CorePlayer for a a fair bit of that time, and it *might* be throttling a little, but no beachballs and definitely no crashes. Yet.

    https://www.amazon.com/gp/product/B011MLC8QE/
     
  16. eyoungren macrumors P6

    eyoungren

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    #16
    Nice! Sounds like your real problem was the stock case fan.
     
  17. RhianB, Apr 6, 2017
    Last edited: Apr 6, 2017

    RhianB macrumors 6502

    RhianB

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    #17
    Speaking of case fans. Back at the turn of the century (1998-2001), heat was my gaming rig's enemy. Long UT, Q2/Q3A, Shogo etc. tourneys were almost impossible due to heat related crashes & freeze ups. Part of it was the midcase I was using (but full towers were prohibitively expensive at the time & heavy to lug around) & the other was the size of the 5500 especially which was huge. I ended up going ghetto and purchased a used, small high powered box fan from a rug cleaning biz that a friend managed. Anyhow, for any intensive gaming, I'd take the case off and blow through the frame with this fan right up against the GPU which was a rage128m or my voodoo5500.

    Like I said, completely ghetto, but it consistently worked for me. Wish I still had a picture of that rig :D
     
  18. eyoungren macrumors P6

    eyoungren

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    #18
    Back in mid-1980 my dad brought home a TRS-80 CoCo. That computer was still around some time in 1985 or so and I used to pull it out to play the cartridge games we'd gotten with it.

    Being better at 15 playing these games then I was at 9 when my dad brought the computer home I ended up playing for long periods of time. That had the effect of revealing a design issue with this computer that I hadn't known existed. It overheated.

    My dad was concerned so he advised that I should let the computer cool down every once and a while. I came up with another idea. At the time we had a small space heater that had a flat, rectangular front. It had an additional feature of simply being able to blow air (like a hair dryer has the non-heat option). Since the top of the TRS-80 was flat and had vents on the top I took this device, turned on the air option, turned it face down and placed it right on top of the vents over the area of the greatest heat.

    I never had any issues with lockup after that and my dad was ok with my idea. Being an electrical engineer he totally understood what I had just done.

    Yet another of those 'fans' I've long gotten used to. :D
     
  19. ziggy29 thread starter macrumors 6502

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    #19
    Our first computer was also a CoCo. I was a sophomore in high school and I got bit by the programming bug because of it, and that's how I wound up becoming a computer science major. I used that thing for hours on end. I don't remember any heat-related maladies with it, though. It did get pretty darned hot.
     
  20. ziggy29 thread starter macrumors 6502

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    #20
    FYI, still trying to stress test it to kill it. Still can't. Maybe I'll just get used to the fan noise and leave well enough alone. :)
     
  21. ziggy29 thread starter macrumors 6502

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    #21
    Finally crashed it due to heat! That said, it was intentional. I'm thinking like a QA department here. I took the rig out to the garage with an ambient temperature of about 86º and started running stuff. And even then it took half an hour to kill it. No need to keep running it out there, just testing some limits. Under reasonable operating conditions it's been rock solid with the new fan.
     

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