Here is two VERY USEFUL sites for you:
http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.htmlhttp://www.notebookcheck.net/Mobile-Processors-Benchmarklist.2436.0.htmlI don't know if you will find an i3 version of the lenovo (because that's much cheaper and the performance difference is small (IN GAMES) if you compare to the i5, but the i5 version is nice too (both new i3 and i5 sandy bridge are strong).
For HDD I recommend 7200 RPM, that's very handy when textures are loading, faster game startups etc.
For video card, I think the Y570 series are only with GT555M which is a pretty good high end card in laptops nowadays. So if you have to go under it, the GT550M is also good, but 20-30% slower than the GT555M. So choose it if that's the last option.
4GB RAM is also recommended nowadays
.
Edit:
And a little personal experience from me:
The cooling is very good, I never had any overheating problems with it.
The material quality is AWESOME.
The JBL speakers are awesome too, very clean sound and a little bass too.
The battery time is also very nice, it can go for 4-5 hours (or even more) if you just surf on the internet, or listening to music.
Playing games on battery can eat it fast (and a film watching), around 2-3 hours, depends on the game.
But I always plug in to the network so no problems, you can play how much you want
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