Momentary Pauses and Graphical Glitches

Question

I'm having the following issues with my mac pro that I use at work. I also have the same specification machine at home without the problem.
1.) During a cold boot (after being off over night) two of the screens become absolutely garbled. Both of the LCD's are connected to an NVidia 7300GT thats plugged into the x16 PCI Express port. I also have another 7300GT that drives an additional monitor that doesn't have any issues. This happens when I boot to OS/X, and when I boot to Windows XP. However, on XP it doesn't happen till I login.
2.) When the machine is warm everything seems okay most of the time. Under OS/X it will occasionally hang where nothing does anything, but then after a second or two everything will be fine. There are little graphics hickups occasionally that go away if I move a window over them. Under XP every great once in a while the screen will become garbled and it will lock up. No blue screen or any error messages. I don't believe its ever the screen connected to the video card in the X8 slot.
These are the steps that I've taken to rectify the problem, but they've all failed.
A.) I did the hardware diagnostics and it reported everything as peachy. I ran both the quick test, and the extended test. It DID however seem rather unresponsive during sections of the testing, but that might be normal.
B.) I reset the PRAM/NVRAM. FYI - it only beeped once and rebooted.
C.) I pulled out the Video card on the X16 lane, and replaced it with the one that was on a X8 pci express lane.
D.) I used the video card from step C on the PCI Express X8 lane, and didn't have a video card in the X16 lane. I don't remember if this test worked because I soon had issues booting it. Apparently it didn't like this configuration.
E.) I removed a hard drive that I put in recently (couple months ago). I can't remember having any of the issues before I put it in. The hard drive seemed fine though. No errors, clicking or any strangeness.
F.) I reinstalled OS/X using a brand new disk, and I also installed Vista on it. Vista showed no signs of issues, and the brand new install of OS/X 10.5.6 still had the occasionally pausing. I haven't tried a cold boot with Vista yet. I imagine the graphics will become garbled. I also haven't used Vista enough to experience the every once in awhile (1 or 2 times a day) garbled screen lockup that I had with XP. I have used Vista enough to know it doesn't pause like OS/X does on the machine. I know OS/X doesn't pause like that normally.
G.) I reconfigured the PCI express lanes so that three of them are X8. I haven't tested the cold boot, but OS/X still hangs occasionally. I haven't been able to determine any pattern to the hanging.
H.) There is no indication in the console of whats making OS/X momentarily freeze
I just want to see if there is anything left to do before I start swapping parts with my Mac Pro at home. There really is only the memory (maybe the cards the memory is on as well), mother board and the power supply. My bet at this point is the logic board.
Message was edited by: Jason Mecham

Answer 1

Update - Despite my feelings that it wouldn't work I decided to try the Nvidia Geforce 8800 GT, and to my surprise it worked.
It solved the issue of momentary pauses within OS/X 10.5.6
It solved the problem I had where 10.5.7 wasn't working at all (it was nightmarishly slow)
It solved the occasional graphical glitches within XP
It solved the cold boot graphics/system freezes I was having within OS/X, and XP
It solved Vista's issue with the graphics driver crashing, and reloading a few times a day.(I never turned it off once vista was getting me by).
I find it really bizarre considering that I have two 7300 GT's and I tried both of them individually in the system with no luck.
I haven't tried putting one of them back in combination with the 8800, but that's my next step. I do want support for 3 monitors.
If that fails I'll try the questionable 7300GTs in my home mac pro. I have a 7300GT in it, and it's still working fine.
If the questionable ones fail than I'll feel a lot better. I don't care about a video card, but I do care that my mac pro is working without issue.
The only surprise in this is how well Vista works with crappy hardware. I mean it just kept running right throw the glitches. It would tell me about it, and where it occurred, and after a reloading the graphics driver it kept on going.