It's okay. But if you plan on playing games then the GT 540M is pretty weak for a 1920x1080 resolution screen.
I have a Lenovo Y470 with a GT 550M and a 1366x768 resolution screen. The two most stressful games I tested it with are Crysis 1 and GTA 4. Both games are slightly old, but they are also still pretty stressful on current systems. It has a dual core i5-2410m. Both games only use 2 cores.
In Crysis with graphic settings at medium I was able to get between 34FPS - 44FPS most of the time in Chapter 2 - Relic. Upping the graphic settings to high reduced the performance to 18FPS - 24FPS the majority of the time. GTA 4 was for the most part pretty smooth with maybe some minor lag here and there. Frame rates seems fine for GTA 4. Sorry no frame rates for GTA 4.
However, the Sony's resolution of 1920x1080 is twice as high as 1366x768. Therefore, you can roughly guess that using the same video card will result in a about a 50% decrease performance. However, the GT 540m is slower than the GT 550m, therefore the drop in performance will be even more than 50%. Probably around 60% - 65%.
The GT 540M should be good enough for low graphic settings while playing at 1920x1080 resolution. Or you can lower the resolution to increase graphic quality.