Kinda lost in this long conversation about temperatures: *I haven't heard a single person say that their computer locked up WHILE USING WINDOWS.*
I've heard a few people mention that sometimes Windows doesn't shut down properly. That's common and old news. But NOBODY has said that Windows has frozen on them in the middle of playing a game or using some intense program.
In fact, I've seen my CPU hit 99C in Windows several times in the course of gaming over a few hours time and it's never locked up. Not once.
Point: I think this still points to a driver/OS issue. Otherwise, we'd be seeing reports of people's machines freezing in Windows too, right? When someone reports in saying they ran X or Y stress test in Windows and experienced a freeze, then I'll agree that we have a temperature/hardware issue going on. Until then, I think that the only people that need to return their machines are those who simply can't afford to be bothered to wait for the software fix.
My tune will change if someone claims and verifies a Windows-based freeze similar to what we're experiencing in OSX. Again, the occasional Windows shutdown freeze is very common, as is the Windows start-up black screen (where it never starts loading Windows).
$0.02
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edit: Patranhadas -
download this wonderful app
http://codykrieger.com/gfxCardStatus and install. it's what we use to manually control which GPU is being used. It will put a little icon in the system bar at the top of your screen enabling you to select which GPU you want to use (or set to auto).
Set it to "Integrated Only" and run the "fish" test. See if anything strange happens.
Message was edited by: Adrian J.