Hello, I have a Lenovo y570 with an intel i7 at 2.4 (i believe) and a nvidia geforce gt 555m. I used to play many of my games on high settings without problems and then i had a hard drive failure so i sent it in to lenovo to get it fixed. they replaced my harddrives which in turn deleted everything i had (forgot to back everything up...dumb i know) and i downloaded a few of my games again and they played perfectly fine and now all of a sudden i noticed that in game performance is horrible. I used to play Saints Row The Third on Dx11 high settings perfectly fine and now i can only play on DX9 because the game will freeze intermittently on DX11 and i dont know what is causing the problem because no matter what graphic settings i put it at the problem persists which leads me to believe it isnt the graphics card.
I have been on the internet, but I check for viruses and malware regularly so I do not think that would be causing this problem.
If you haven't been on the internet and you've ran anti-virus/malware software and it came up with nothing then I would blame the drivers. I would try the drivers from Lenovo as Pyree said and see if that does anything.