nVidia Software Lags Hardware 
I'm working with the x86-1.0-2880.tar.gz version and having a similar problem. What I've learnt so far is that the nVidia driver, which you will find installed on your computer (probably under /etc/X11/nvidia.o) first queries the PCI bus controller to look for an nVidia chipset, and gets back a list of all the devices attached to the PCI bus and the AGP slot (if you have an AGP slot...if not, it only reports what's on the PCI bus). Appendix A of the README file from nVidia (probably at /etc/X11/X86-1.0-5336/README) lists a bunch of different nVidia chipsets and the ID numbers they regurgitate when queried by the PCI bus controller. After reading this particular README file (there are about 15 different files called README something-or-other that get installed with the nVidia driver), I discovered a funny thing. The FX5200 is not listed as an officially-supported chip that the nVidia driver is expected to run.
That's a problem...particularly since I blew 74 bucks on the nVidia card. So...
Here's what I learned. nVidia distributes what it calls a multi-platform driver. You've got version 5336. I've got version 2880. The multi-platform driver is supposed to work, interchangeably, with every nVidia card ever made. Only trouble is, the Windoze version doesn't give two hoots what number the PCI controller reports back, usually because whoever built the video board went to the trouble of writing two lines of code into the Windoze driver module to tell it to go ahead and use the nVidia chipset to display video. We Linuxians have to make this adjustment the hard way, by manually editing the /etc/X11/XF86Config-4 file to tell the driver that the video chipset is a video chipset.
When I get home tonight, first thing I'm going to try is to edit my XF86Config-4 file. The starting point is to read the /proc/pci file to learn what it calls the nVidia chipset. I found that the answer is "0x330" for the GeForce FX5200. Then, I'm simply going to add a line to the XF86Config-4 file, under "Device", to say "chipset 330". I'll let everybody know the results. If it works, it should fix the problem. If it doesn't, I guess we'll all keep on trying until we solve it.
When we do, we should make sure that folks get notified about the change that needs to be done to get FX5200 on the road. BTW--do you know that some of the nVidia GeForce FX5200 cards, such as the one from MSI, have partitioned video memories to support double-headed monitors? I thought I had a dead screen on my VGA port, and after turning the brightness up full on the monitor, I saw some dimly-readable text. Then I plugged the S-Video output into a TV set, and got a perfectly-readable black-and-white picture! If you've got one of these funky cards with multiple independent outputs that are run by one FX5200 chip, it would be worthwhile to check all of the outputs to see what's coming out of them in text mode...and in graphics mode, once we get up and running.
nVidia GeForce FX5200 support
