Minimum spec

[Red Harvest]

Processor is no problem.

There aren't many games these days that do well with only 256 MB of RAM. WinXP needs about 512 MB for proper operation anyway (if you want to run apps quickly that is.)

The 8500 is a good card but it is getting a bit dated. The regular retail 8500 was fully a match for any GF3 or GF3Ti. I doubt it will run the shaders at an acceptable rate, but I could be wrong. Still that should be adjustable. An 8500 is a half generation below a GF4 Ti4200, although the AIW you have used a lower clock and memory speed variant of the 8500 so it is taking an additional hit. If you are using the AIW features and want them in future cards, upgrade options get expensive.

[ToranagaSama]

The 8500 also isn't a DX9 card, which is what you need for the latest games.

Here's a slightly dated Chart outlining the basic features of several cards: VGA Chart III

This is the latest Chart, part of a comparision article: VGA Chart IV

[Akka]

I had a small LAN in my flat last week-end with friends.
We did some RTW network games, with usually between 3000 and 4000 soldiers in each battle.

If was laggy, but playable, on my second computer, which is :

1700 + underclocked (the MB can't run at 133 MHz, so it runs at 100 MHz, which means that the processor is roughly a 1400+)
896 Mo of RAM (SDR PC 100)
GeForce 2 Pro (yes, it's a GF2, not a 3)

All the graphical options were to the lowest setting (except for unit size, which was set to "large"), which is quite not as good as the highest one, obviously, but still much better than what I expected.

So, except perhaps for RAM, I wouldn't worry for your own computer ^^