Look at the difficulty of Litecoin vs Bitcoin
Bitcoin has a much higher difficulty than Litecoin higher difficulty harder to mine.
Litecoin uses another Algorithm than Bitcoin (Scrypt vs SHA256)
So calculations are different - with SHA256 the speed is measured with MH/s
on scrypt KH/s
You cannot actually compare what is faster to mine.
Rather compare the higher profitability and at the moment and that is litecoin.
If litewcoin take off no one knows maybe maybe not.
You have a hardware comparison for litecoin and bitcoin
https://en.bitcoin.it/wiki/Mining_hardware_comparisonhttps://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparisonCheck the speed for your GPU
Cheers