I don't really know how much knowledge do you know about the graphics card of PCs and laptops.
1. basically Nvidia card are better for games for many game developers will make special optimization for Nvidia card.
2. There mainly two graphics card brand on market: AMD (former ATI) and Nvidia. Since about 2006, both manufactures have used this f**king strategy of confusing card numbers. Now, it doesn't mean a card with a bigger number would be better.
3. for Nvidia, they have 3 levels:
GTX > GTS > GT.
for each level, like GT 540, the first means the generation, the second number means the level (higher the better), the third number also higher the better.
for AMD card, like AMD HD 6850:
the second number tells us the level:
4 and 5: low
6 and 7: mid
8 and 9: high
The third number higher the better, the highest would be 9.
the 4th number is always be 0.
4. technology
for now the highest is GDDR 5 which would bring 40% higher performance for the same card in GDDR3.
The first GDDR5 is out in 2008, and popular since 2010.
the above 2 cards are both in GDDR3, so it is not good enough.