For the first one, I don't know much about AMD but it's quad core so it's probably decent. Actually I looked I this website, And based I this chart the second of has a much better processor than the first.
However it seems that the second pc has a better graphics card than the first. It's a toss up.
I would reccommend the XPS because my XPS laptop an run most games on at least medium settings. I usually have no problem running my games on high settings with low shadow and water detail settings. I don't care too much abou that kinda stuff.
XPS computers are known for their high performance. It's basically the next level down from Alienware.
I think HP Pavilions are more business grade, so I suggest the XPS
Don't get any branded shit, just get custom build stuff off smaller online retailers. Better specs for the money. On ebay you can check the user feed back and seller rating, so it isn't a risk.