"I've got an i7 iMac (ATI 4850) that has been displaying a mild version of the graphics corruption issues; when doing a long CPU-intensive activity (say, a video encode using 200% or more CPU), I will start to see very brief static-like horizontal bars flash on the screen every minute or so after maybe 30 minutes of processing. It is perfect otherwise, which makes me think it's in some way heat related (though all temperatures reported by Temperature Monitor are within normal range).

(I wonder if anyone with this problem has tested with an external display to see if it also shows the problem. After the rumor of a potential cable issue (with some builds) I'd be curious if anyone had taken one apart (or had apple service do it) to verify there's no cable damage/pinched cable, etc. Just thinking out loud but if anyone with this problem has tested with an external display (or I missed some apple forum post on that) let me know.-Mike)

I installed the GPU firmware update yesterday, but tonight on an iDVD encode confirmed that there are at least some glitches still happening. They seem to be less frequent, though in my case they were so sparse and sporadic to begin with it's hard to say for sure.
At this point it's mild enough that I'm not bothering with AppleCare, though if there aren't any further software/firmware fixes published once stock has stabilized I'll be seeing about a fix while it's still under warranty.
Otherwise absolutely fantastic computer, and gorgeous screen...
-Marc"

A later reply regarding external display tests:

"Just a response to your query about external monitor tests for corruption with the 27" iMacs. Here in our office, we just replaced two G5 towers with a pair of 27" iMacs. One was dead out of the box with no backlight. The machine booted, but you couldn't see anything. It was promptly replaced (relatively speaking) by Apple.
The 2nd unit would occasionally flicker out for about half a second, maybe once an hour. The Cinema Display attached to it would not flicker at all. It has since stopped doing this, so I'm holding off on the firmware patch until the majority of replies are positive. The replacement for the dead iMac has been flawless from day one.

(The reason I asked for external display tests is if the problem was GPU (or vram) related (overheating, corrupted video ram, etc.), it should also show on the external display not just the internal one. (A screen capture of the display when the problem appears also would be a way to test for that - if the problem was due to corrupted vram, etc. the screenshot file would show the corrupted display image.)
And for the record I asked Peter if the replacement iMac had the same graphics rom version, etc.-Mike) Both machines are running ROM revision 113-89110C-394, and EFI Driver Version 01.00.367 on an ATI 4850. I had the same thoughts about the overheating, as well. If it was the card, why no external corruption?
I ran a QMaster H.264 batch encode on one earlier this week, with 6 threads running. It ran no hotter than usual, even though all eight 'cores' were maxed. Power draw did go up, however.
-Peter M."

Noticed the WD 1.5TB drive issue (report), I've had one installed in my Mac Pro for a couple of months now and had no issues, I've got the drive installed in Bay 2, partitioned as a Time Machine backup, Render HD for FCP and general storage.
I went for the 'green' version as I wasn't bothered with speed and wanted to keep the Mac Pro as cool as possible, so far so good...
Model: WDC WD15EADS-00P8B0
Revision: 01.00A01 (drive firmware version)
System info: First gen 2.66Ghz Mac Pro, 10.6.2 with latest security and java updates.
-Phil"

Phil later sent some XBench results from his drive, which showed performance about what I'd expect from these drives. And I've had other 1.5TB GP owners write they've had no problems - clearly Jim's problems are not common (and nobody else I know would have bought "green" drives for server RAID or any other raid array for that matter).
Some replies suggested WD should note that on the box, but I'd never before heard of anyone trying green drives w/RAID. I doubt WD will ever do that, as they probably consider that like Toyota putting a note on the Prius' window sticker that it was "Not recommended for Racing".

I may pick one of these up for myself just to see if I have any problems in a Mac Pro (all bays are full now but I can swap one out for some tests for a few days). And if it checks out ok, I could use it in my FW connected Ministack (where as I said before I wanted a cooler running drive), although I'd prefer a 2TB model. (My 1TB WD Green HD in the Ministack is getting pretty full after a year of use - it's partitioned for TM backup, general storage and a clone of the iMac's boot HD. And not smart I know to put all the iMac's eggs in one basket so to speak.)

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