My mac Mini has problem rendering images and video

Question

THE PROBLEM:
My mac mini has problem rendering JPEG image. There are strips on the images. Other images such as GIF, PNG, TIFF, and BMP are displayed nicely.
The images shown in the links below illustrate the problem:
http://www.flickr.com/photos/terencewong/71481156/
http://www.flickr.com/photos/terencewong/73360989/
(Please note that this image is grabbed from my faulty Mac Mini and saved into TIFF. For uploading purpose, I converted it into JPEG on ANOTHER computer.)
For movies, AVI can be playback without problem. But when it is converted to MPEG, it looks like an untunned TV channel.
FIXES TRIED:
I did erase and install 3 to 4 times using both the install disc and my Tiger Family Pack. All ended up with strips on the JPEG images and the generated MPEG movies.
I've also tried to flash the firmware to 113-xxxxx-124 using ATI's october 2005 universal ROM update, however, the ROM Revision shown in System Profiler is still 113-xxxxx-116 no matter how many time I reboot the system.
INVESTIGATION:
Yesterday, I did some research and got to know that JPEG and MPEG are using DCT (Discrete Cosine Transform) for decompression. And the ATI Radeon 9200 chip provide such a transform on hardware basis, which free the CPU from doing something else. Feel free to point out my inaccuracy.
HARDWARE SPECIFICATION:
I bought the Mac Mini in the last Februray.
The system Boot ROM version is: 4.8.9f1
Display card is ATI Radeon 9200
Chipset Model: ATY,RV280
Revision ID: 0x0001
ROM Revision: 113-xxxxx-116
A POSSIBLE CONCLUSION:
I suspect that it is this part of the chip (the DCT) that is faulty.
Anyone know how to fix this problem?
Many thanks!

Answer 1

Assuming that your display is tightly connected, thus the problem is not caused by something as simple as that, the fact that a full erase and install has not removed the problem would, I think, point to this being a hardware issue, and given that everyone's mini (with the possible exception of some of the latest ones) has the same video chipset as yours, and do not suffer the problem that you appear to, it seems very likely that your mini has a fault which is in need of repair.
If you have an Apple Store nearby, I would take it there to have it checked out - at the very least they should be able to replicate your problem using an in-store display, and if not, thusly suggest it's something external to the mini and concerning your display or something very unusual in the immediate environment of the mini. If you don't have an Apple Store in reach, I'd take the system to an Apple authorized service provider since at the present time it is under warranty.