I have the y510p with the dual 750m GPUs, but the SLI function does not work until Nvidia releases the drivers. In which case, I run the game on Ultra setting around 40FPS in town, but I haven't tested this in a PVP setting yet. Personally, I recommend getting the SLI setup as it is the best value. If you need a DVD drive, I bought an external one that I rarely use. Otherwise, I'm very impressed with the performance of this Laptop even without, rather especially without SLI drivers... I did ALOT of research and you CAN'T find one with the same value and price comparison. I'll argue that till my face turns blue lol.
You probably already know that, but I say it anyway : IMO, laptops are terrible for games. I think this is a bad idea.