I just installed this along side my Ubuntu x64 partition, and my initial reaction is wholly carp is it slow!!!!!!
AMD 64 X2 5400
NVidia 8100 onboard
System monitor shows my CPU averaging 40% on one CPU or the other while the system is doing nothing at all. youtube videos flicker, out of sync, latency so bad it takes ~20 seconds to pause the playback. last.fm streams ok, but CPU usage is all over the place, whereas under Ubuntu/derivatives I don't notice any activity on the CPU monitor at all.
Then I enabled compiz. Ouch. I can't even scroll a browser window without stutter. I realize the onboard chipset is less than optimum for compositing, but this is the first distro I found it actually unusable at even the leanest config.
Another issue I have is, where's the volume? I've got everything bumped to 100% and only have about 25% the volume I should. At the current settings, the audio should have me plastered against the wall!
I'm going to do all the system updates to see if the latest kernel, etc, makes any difference, but as it stands now the x64 version is unusable on my system. Anyway, I'm not trying to be critical, just relating my experiences 30 minutes into my install and I guess I was kinda expecting Mint to be a little leaner and faster than sluggish bloat Ubuntu has become, so its a bit of a surprise to see such poor performance.