When it comes to gaming, in my experience, the best overall ATI driver is the latest one available for Win98: Catalyst 6.2. It's not perfect, though. There will be some games that have issues (i.e.: Incoming), but most will work very well.

As for the FX5500, the best driver that works with it is 45.23, but it won't work out of the box, you will need to force the installation of the "FX 5200" driver.
Some people have also had good results with 56.64, but I myself did encounter some issues with it (such as slower performance in some titles, on certain platforms).

Now, one thing to keep in mind is that the behavior of these cards and their drivers is HIGHLY dependent on the platform.
Depending on your other hardware, the experience can be very good or.... VERY bad.

So, my recommendation is NOT universally valid. In fact, on some platforms, I would not even dare to use an FX5500 or a Radeon 9550 in the first place.

Hi @bloodem

Thank you very much for such a very informative response!

I'd like to ask about the same (stability) for the VIA 4-in-1 chipset drivers on ASUS P4V8X-X (PT800 chipset) mainboard, for Windows 98SE.

What version should be the most appropriate one? As I read/heard, the latest/recent versions of VIA hyperion drivers are not really optimized for Windows 98SE.

Any clue on that, too?

My specs are: Pentium 4 - 1.80 Ghz - 1 x 256 MB DDR400 RAM - 120 GB IDE/PATA HDD.

Best wishes.

Echo'ing what Bloodem said.

I have used the 45.23 drivers on loads of Geforce FX cards (5200, 5500, 5600, 5600 Ultra) all of which worked great.