I am running LR4 and was on an HP tower, 32 bit, 3 GB ram, Quad processor,, would say it was fair but could certainly be helped,, NX2 was slow at times,,
since I have an 800E on order and my tower is three years aged I figured I would go for a new tower,, have a good 24" HD monitor,,
todays machine is 64 bit, has i7 3770 processor with 16 GB ram,, lightroom or NX2 opens in a flash and could not believe how quick it is,, even the wife had to say WOW when I was running through some old photos as they were on the screen in a flash,, even the internet is far quicker,, our home has a 30+ MB download and 4.5 MB upload,, if the remote site is fast it is on the screen when removing my finger from the key,, the wife's Ipad is also almost instant,,
the new machine does not have all the junk the mfgs usually load on them, just the basics needed to operate,,
I'm loving it,,
Derry