Which Laptop Is Better For Casual Gaming?

Which of these 2 laptops would be better for casual gaming, eg. GTA 4, Team Fortress 2, Garrys Mod etc?

Lenovo G505s:
Screen size - 15.6 in - 1366 x 768 No
Processor - AMD AMD A10 A10-5750 - 2.4 GHz
RAM - 6 GB
Hard Drive - 1 TB
Operating System - Windows 8.1 (64-Bit)
Optical Drive - DVD Re-Writer
Graphics - AMD Radeon HD 8570M
Graphics Memory - 2 GB

Dell Inpsiron 15R 5537:
4th Generation Intel® Core™ i5-4200U Processor (3M Cache, up to 2.6 GHz)
Windows 8.1 (64Bit) English
AMD Radeon™ HD 8670M 2GB DDR3
8GB 2 DIMM (2x4GB) DDR3L 1600Mhz
1TB 5400RPM SATA Hard Drive
39.6cm (15.6") LED Backlit Display with Truelife and HD resolution (1366 x 768)

Note: I would be installing Windows 7 on whichever I get straight away.

The most important thing is the graphics card. I'm a little lazy today so I'm not gonna check which one is the best. Just search on google and compare the two with the benchmarka you get.

Acer