# iMac Video Card Meltdowns



## godsavant (Oct 27, 2010)

Hello all,

I've recently ran into a problem with my 20-inch aluminum iMac, which I've partitioned into 1/2 Mac Snow Leopard, 1/2 Windows 7 via Boot Camp. I've had it this way for over a year, and have been gaming quite heavily on the Windows side (thanks to the upgraded ATI HD-series video card I ordered when purchasing the computer), and now have it as my default startup OS. 

In my first year of college, I lived in a dorm, where the computer was stationed near a window I usually kept open; it could run nearly any game beautifully, from Fallout 3 to Oblivion to Fallout 3. I often played for hours on end, and though the computer's aluminum casing would often get quite hot, it would never result in any performance issues.

However, I've now moved it into a spacious but windowless interior bedroom, though I the computer is positioned close to a door; since then, I've had the sudden black flashes on the screen during gaming and subsequent Blue Screen of Death for a few seconds, followed by a failed reboot (the computer will elicit the Mac startup chime and start some faint whirring noises, but the screen will remain black). This is only resolved when I unplug the iMac from the wall and leave it to sit for a few minutes, after which it starts up normally (albeit in the 'unexpected shutdown' screen'). This has occurred in multiple games, Left 4 Dead 2, StarCraft 2 (only in post-patch, interestingly enough), Bad Company 2 and Titan Quest among them.

After some asking around, I was told that this is most likely caused by the graphics card overheating and automatically shutting down, due to the graphical stresses of high-res gaming. Now, I'll admit the upper back of the computer doe get quite hot some time, and that the move to a lack of air circulation in the room may have something to do with it, but I _can't_ be expected to believe that my computer - once able to play Fallout 3 and Mass Effect 2 on maxed resolutions for hours on end only a semester ago - is now incapable of running Titan Quest on lowest possible setting for even _twenty minutes_ without melting down like this.

Hypothesizing that my fans may not be sufficiently cooling the interior, I downloaded smcFanControl for OS X and turned the minimum fan speed up to half of the available scale. This did nominally prolong my gaming time, but the computer still eventually Blue-screened and melt down as I expected.

So now, I am at a complete loss; what factors in my new environment could have caused my iMac to turn into such a wimpy grilltop? I turn to you, Tech Support Forums, for counsel. 

Thanks for any solutions,
-Dave

P.S. If this would fit better under Gaming, please let me know; I figured this was more of a hardware issue.


----------



## sinclair_tm (Mar 11, 2005)

I find it hard to believe that just moving would do this to you. I play Fallout 3 on my aluminum Macbook in my room which has very poor air flow, and don't have this issue. Turning the fan speed up in OS X will not help when running Windows. To change the fan settings on my Mac in Windows 7, I use MacFan0_65. It's a command line utility that changes the slowest fan speed. I'll run it and set the fan to 4500rpm before starting Fallout 3. I don't know if it works with iMacs, but it's worth the look. I see you have L4D2 in you list of games. Did you get that through Steam? If so, install Steam on your Mac in OS X, and then download L4D2 (if you buy the game on one platform in Steam, then you can play it on any platform it's supported on in Steam) and play it in OS X and see if you have the same screen issues. If you do, then I'd say open the iMac up (if you are brave and out of warranty) and make sure that the fans are not clogged with dust. If the insides are clean, then you'll have to take it to Apple for a repair. If you don't have any problems, then go back into Windows and make sure that you are using the Apple supplied video drivers, and not ATI's. The Apple hardware is different enough that people have had issues using non-Apple drivers. Another thing to do is to check your video card temps. In OS X I use Temperature Monitor Lite and in Windows 7 I use CPUID HWMonitor. HWMonitor runs in a window and I start it before gaming, and then every so often durning the game I'll alt-tab to it and see what the current temp is, and what my max was. It's been a long while since I've gamed, so I can't tell you what temps I'd normally get. Maybe if I get my homework done soon, I'll hop into 7 and play some Fallout 3 and let you know.


----------



## godsavant (Oct 27, 2010)

sinclair,

Thanks for the speedy response. About smc_FanControl, the fan-speed alterations made in OS X do carry over to 7 if I reboot directly into Windows afterwards, though the settings are lost once I shut down...not that it helped. I've consulted with my university tech office, which has indeed surmised that it might be a dust buildup causing the overheating. I've scheduled to take the computer in tomorrow morning and have them check, I'll report the outcome as soon as I can.

-Dave


----------



## godsavant (Oct 27, 2010)

It appears that the problem was indeed dust buildup inside the computer; after lugging the heavy computer to the office, having it cleaned, and carrying it all the way back, the computer has performed close to optimum efficiency; it takes several hours of continuous gaming before it begins to get hot; of course, afterwards the screen does begin to flash black, but I'm guessing that's some permanent damage done to the video card, what with all the overheats and all.


----------



## sinclair_tm (Mar 11, 2005)

That is possible. I'd be sure to keep the fan at full speed durning gaming, and watch the temps. Try to not let it black out again. The more it does it, the sooner it'll die for good.


----------



## godsavant (Oct 27, 2010)

sinclair,

That's what I'd feared. I've taken the crude but effective approach of plugging in a huge room fan behind the computer's exhaust slit, and so far it's actually done wonders for keeping the computer cool and functional; the only time I still experience blackouts is when playing certain games (and I suspect there might be some amount of dust they didn't get to), but that's a big improvement from my previous predicament.

Um...is the room-fan solution frowned upon in higher echelons of computer maintenance? I'd be glad to go with a more elegant, less noisy solution, but all the external coolers I can find are for notebooks. :normal:


----------



## sinclair_tm (Mar 11, 2005)

Any form of cooling that the user can stand is a-okay. So, if you can stand it, then there is nothing to fear. I've known several hard-core computer geeks that point big fans at their open computers to keep them cool enough to run. 
On the games you still have issues with, turn the graphics settings down. Yes, it won't be as pretty, but it'll be kinder to your GPU.


----------



## Jaygyver (Nov 4, 2010)

I'm not familiar with iMac's as far as where they get hot, the top round part?
You might just get a small 3 or 4 inch box fan or such and point it at the hot part, that way you have most of the cool air directed at the hotter part instead of the whole area.

Just a thought....


----------



## Jaygyver (Nov 4, 2010)

Oh... never mind,
I had a 60s flash back, I was thinking they still had the bubble bottom......


----------

