Almost all notebook PCs have down-rated GPUs that are about 20% slower than the desktop GPU with the same core processor.
I'm dubious about the usefulness of GPU Boss's comparison this time, however:
http://gpuboss.com/gpus/GeForce-GT-640-vs-GeForce-GT-540M
That set of numbers seems to be down-rating the GT 640 desktop card also, making the 540m look less weak.
Next, we look here: http://cpuboss.com/cpus/Intel-Core-i5-650-vs-Intel-Core-i5-2430M
That comparison really flogs your slower CPU.
You probably should visit Game Debate's website and get their comparison as well. I usually don't trust SR Labs' results, although if that's where your screen shot originated, they seem on the mark today.
