Okay, I'll post a couple of pics later.
So far I updated it (drivers, BIOS, Windows) and installed a 4GB DIMM with the help of
this video (which wasn't strictly necessary, it's pretty easy). Now I have 5.60GB available for Windows (384MB goes to video RAM, the rest is probably a rounding error).
The only software I installed was Microsoft Security Essentials and Everquest II Extended, the latter because I was curious about what performance I'll get. I plan to later install Visual Studio and VirtualBox and a web browser (not sure which one yet).
Boot time is awful. I just measured about 2.5 minutes to desktop, and another half a minute until it's usable. I can only hope Windows tweaks itself to reduce that time. Not that I normally do a clean boot, but I'm sure resume from hibernation will be quite slow too, considering the amount of RAM (I'll measure and update the post).
Edit: Actually resume is a very reasonable 23 seconds including the time until windows starts which is about 9 seconds. So I can certainly live with that. I don't know if the amount of memory used at hibernation time affects this, I guess I'll find out with time. The test had nearly nothing open. Resume from sleep is nearly instantaneous.
EQ2X runs well enough for my needs (especially considering I hardly play), as long as I stick to low settings without any fancy effects. Interestingly texture size doesn't measurably affect performance, even though the highest settings is supposed to be for cards with 512MB of RAM, and the X120e only gives the Radeon core 384MB (though granted that may be enough for my limited testing and will have an effect in more complex scenarios).