Radeons only started to get good with the 9000 series. Anything before that is, TBH, even worse than Geforce

A better card does not always mean better performance. A really important thing is your bus speed (and memory speed) as well as your OS.
If you put it to a table its like:
Win95 - 100% performance, crashes all the time (100% since it's reference), also it's not compatible with today's needs
Win98 SE - 70 % performance, pretty stable
Win ME - 20% performance, crashes like crap, acts up, and has Microsofts little trick inside
*1 Win XP is better again when it comes to performance, still not as great as Win98 SE
*1: Since Windows ME, Microsoft uses the following trick to fool customers: You will get to see your desktop quite soon in bootup but it's only a fake to prevent the user from seeing the system is not even half way booted yet. So it just gives you the waiting curser and you cannot open any tasks while Windows finishes booting slowly. 