Gti - this is my ghetto HTPC, not my main terminal

Up till now, all my HTPC had to do was run XP, WMP11 and VLC - all the data etc is all stored on a NAS server upstairs, so all it does it play either mp3 or video using WMP and VLC respectively....
But I've been thinking about running either MCE or MediaPortal on it, and I need RAM for that, as 128mb ain't gonna cut it

It has a 1.8gHz P4 in it, so the theory was it should be fine...
However, after installing MediaPortal on my main PC, a 2.8 P4 with 1.5gb of RAM, it seems very slow to do anything, so not sure about bothering on the HTPC anymore... don't wanna spend £30 odd quid and find it is slow, as slow is frustrating, and at least now, just using XP folder view to navigate is quick and painless....