It's about the processor, isn't it? Acer is usually a hit and miss. Sometimes you'll get lucky and have a great one, other times (mostly) you'll get a "lemon" or a poor one. Rarely I find that people have no problems with them (eventually).
Look towards Asus.
Also, if that laptop is using an integrated graphics card (uses RAM) instead of a dedicated graphics card (has it's own memory), you'll experience a lot of problems.
I don't know much about AMD cores, but a quad core in a laptop (especially acer) for that cheap seems to me it's one of the older quad cores, in the c2d level range.
Here's a small list in order of 'important' things to look in a computer for the gamer. (The one which the most general user cannot comprehend)
-Processor
-Graphics Card
-Ram
It's as easy as that ;b it's weird how in stores I always see these moms, teenage girls, and even the employees explaining "well it has a 500gb hard drive so that's better than 320gb harddrive, a 17.3 LED HD screen, 4 USB ports, one is 3.0 compatible, a super sound card, 2gb ddr2 ram, and is an intel celeron core! for only $599, and a 3 hour battery life. This is a sure buy!" (completely forgetting the integrated graphics card, since that obviously is not important .../sarcasm) when next to it I see the Asus u52 bamboo with i3, nvidia gt 320m, 4gb ddr3 for only $559. ._. not to mention the asus has 7+ hours (10 advertised) of bat life, especially with optimus.