can it give better performance in latest games ? my specs are intel core2duo E7400 @ 2.80 ghz and 2gb ram?screen resolution is 1366x768p
for latest games... your pc is kinda old. 2 gb system memory is marginal. 4 gb ram would have been better. cpu speed is also lacking, not to mention older architecture.
for 1366x768, radeon hd 6750 will be better than gt440.
do you know how much radeon hd 6770 costs at your location? if 6770 costs similar to 6750, then 6770 is the better choice.