Yes, It has 8 GB of DDR3 RAM running at 1600 MHz. That page says nothing about the vram though.
Most of the time the two are within 20% of each other. The samsung wins at skyrim fairly well at enthusiast settings, but the gddr3 clevo creams the gddr5 samsung at civ 5. Considering the two are using different drivers I would say that the two are roughly identical (the clevo gets a higher 3d mark 11 score).
Also remember that the 640m is clocked lower and so will need less memory bandwidth than the 650m.
I doubt that you will see an increase in fps by 3.5 times (100 fps vs 350 fps) by doubling the the memory bendwidth, especially since the 640m can't use all the bandwidth. The 650 ti (almost twice a powerful as the 650m) has a 128 bit bus operating at 1350 mhz. More likely the op is using the intel graphics.
I have a 660m (overclocked to 1058 Mhz compared to about 600-700 for the 640m) and I have never seen the memory controller load go over 60% or about 48 GB/sec. 32 GB/sec should not really have much of an effect on the 640m.
