Do TDK (CD-RW) work on Matrix, if not what do and on what burning speed.

If a CD-brand work on a Xbox does not depend on the chip but at the DVD-drive.

I have been using TDK CD-RW with no problems in 20+ Xboxes. I burn them at 4X.

I used a SmartMedia CD-RW. just make sure that you finalize the cd and burn at slowest speed possible b4 burning. should work

All xboxes vary. Your best bet is to buy a single cd of each brand and see which runs (and if a few run which runs fastest) Many times memorex, imation, and a few others work.