Nvidia gtx 650 1gb ddr5 is better or gt 730 2gb ddr5 ???
The 650 is the better card- whilst it has less memory, it has a higher core speed and double the memory bandwidth (so the memory is faster). As a result games will run better on the 650, unless you have a very high resolution screen (where the amount of graphics memory might be too low), but in that case you should be able to get around it by lowering settings to reduce vram usage.
Better at what? Are you wanting to game with them, if yes what games and resolution? Both are very weak by todays standards so if wanting to play modern games it might be neither are good enough for what you need.