I won't be able to help you, mrnegitoro; I'm far too new at this stage.

What I will say is that maybe someone else will be able to if you provide more details about your setup.

What distribution are you running (e.g. Zephyroth's 10.5.2 rev2) What kernel? Is your 7300GT the 256mb one?

My 256mb 7300GT works with Zephyroth's Universal Installer on Zephyroth's 10.5.2 rev2 release, using the 9.0.0 kernel. After installation I am able to select up to 1360 x 768, which is the only resolution I have tested. I'm assuming the lower resolutions work fine also, but I have not tested them so I cannot confirm.

Good luck though, I hope someone can provide you with some assistance :-)