I keep saying I'm going to upgrade mine but...
I'm running on a Dell desktop that's about 6 years old, 1GB of RAM. It's been running 24/7 as long as I've had it.
It runs:
VWS
WD
StartWatch
VirtualVP,
CWOP uploads
Uploads to WU, Hamweather, etc
Fling to two websites
WXMesg Server
WD SQL uploader
GRLevel3 with uploads
Chugs right along. I restart it automatically every morning at 5am and I never have a problem.