ATI Radeon 92x0 Resistor Mod for Mac Use
To the best of my knowledge, these resistors must be in the correct positions for any 9200 or 9250 AGP or PCI card (built on the ATI reference board design) to work when flashed with a Mac ROM. Some cards are built on other board designs, and may or may not have different resistors that may be just fine, or may need to be moved.
Sometimes one or more of these resistors is already in the correct place, but when that's not the case, they need to be moved. This requires skill in surface-mount soldering; if you feel you haven't the skill or experience to perform the operation, it's best that you contact your favorite local Electrical Engineer or electronics repair professional. Either that, or call in the A-Team…I mean, consult The Mac Elite forums, where you should be able to find a member able to help you.
If soldering is too intimidating for you, another option is to head over to your local auto shop and pick up a tiny bottle of rear defogger repair solution. It basically looks like liquid copper. Pop the resistors off, then use a toothpick or other small implement to place a little drop over the desired resistor surface mounts. Give it a minute or two to dry, then carefully scrape away the excess with a small knife so that the dried copper solution is only contacting the two points. Since these tiny resistors aren't really there to resist anything, this poses no problem at all and can be an easy alternative to a hot soldering iron.
These pictures, originally by TomeJapan, show the area of the card you should be looking at, and the correct resistor configuration there. The resistors are located on the back of the board, near the center. The resistors we're working with are in the red boxes:
They must match the configuration shown below. If any don't match, change them so that they do.
Here are some pictures of 92x0 series cards built on the reference board design (for identification purposes only - the pictures below don't show any resistor changes).
Pictures taken from iXBT: http://www.digit-life.com/
These guys take lots of high-res pictures and scans of video cards, and are a good resource to the modding community.
PS by TomeJapan:
For other cards, move resistor R229 to R230.
Actually, RADEON9250 PCI or AGP cards can also be accelerated under OS9 with drviers I made. Feel free to send me an PM and I will be glad to help you. Be sure that you must let me believe that you are an end user but not an e-bay (or other sites) seller.