So overall I'm summing up the solutions that could best do to reduce the lag to some games for people who are new to this thread.
1. Generically, first make sure your Nvidia is turned on by the metal switch on the bottom left of the laptop WHEN your computer is on (Light turns on when it's on). (BTW I love the manual graphics switching other than automatic in my opinion)
2. Switch the battery options on the battery options (windows 7) to high performance and lenovo battery options (one of the icons on the taskbar) to high options as well. Also on the Lenovo Energy Management, click on the Power Scheme (the blue cog wheel on the bottom next to the question mark and the i), go to the Smart Power Saving tab, and uncheck both.
[http://forum.lenovo.com/t5/IdeaPad-Y-and-U-series-Laptops/Y570-Games-lags-and-choppy-when-it-s-plugged-in/ta-p/502355]
*NOTICE* Sometimes when playing heavy sand-box games where your graphix card will sweat the most, some people recommend setting the lenovo settings to energy star which may show smoother but lower fps.
3. Go to the laptop2go site to download driver 275.33, the bottom link and download both the driver and the inf file and replace the inf file in the original driver folder with the separated one.
[http://www.laptopvideo2go.com/drivers/win7x64/275.33/disclaimer]
(Most of you will not be able to download the legit driver from nvidia as the common error message that the **bleep** driver can't find any compatible hardware, so we try to improve).
*NOTICE* It may be just my y570, but before I installed this 275.33 driver from laptop2go, Bioshock 2 ran fine. Now, it seems to lag profusely, and I tried reinstalling and it is a bought game so don't question the legimitaticy.
I'm somewhat a heavy gamer and before the changes I made (except for #1 and half of #2), Battlefield Bad Company 2, Resident Evil and some other games could play from medium to high settings. As I mentioned above, Black Ops, Resident Evil 5, Assassin's Creed 1, 2, or Brotherhood, Mass Effect 2, Borderlands, Arkham Asylum, Fallout, Starcraft 2 are all playable, with high settings.
There's been a strange occurence to me when I play heavy sand-box free-roaming games like GTA IV and Dead Rising 2, as it sometimes gets smooth (even when its plugged in) and sometimes it gets choppy. (Crysis has some choppy problems as well, but not has heavy as the two mentioned above). And when it's choppy I wait for a bit and it gets smooth after 5-10 minutes of choppiness. Over-all, these three solutions are what this thread has displayed, and I'm just summing it up so people don't have to look arond all pages.
Thanks to Kirill, M47R1X, defjam.