Given the two choices that you have, the ATI is a better choice because nVidia is just rebranding their old graphics cores and selling them. If you look at the specs carefully, you’ll notice that many of their 9 series cards were just rebranded 8 series cards which are now again being rebranded as GT, GTS & GTX series of cards except for the DX10.1 support and a smaller fabrication process reducing heat and power consumption but only on a few of those cards. ATI, on the other hand, when it comes out with a new series, it is a completely new architecture with better performance and a different new core. So, go for the ATI 4570 than nVidia’s G105M for your laptop.
ATI Mobility Radeon™ HD 4570 with 512 MB, no doubt about that.
GTS105M is rebranded 8400M GS
*www.notebookcheck.net/NVIDIA-GeForce-G-105M.13790.0.html
*www.notebookcheck.net/AMD-ATI-Mobility-Radeon-HD-4570.13885.0.html