And me who though the mining is related to CPU and RAM , so basically a laptop with low GPU or no GPU at all can't mine? Intel HD Graphics users can't mine bitcoins , right?
Bitcoin can only be mined through ASIC today. No CPU, not GPU, even FPGA.
The GTX 750 is very good for mining CryptoNight. However, this is for small miners. You can buy like 12 GTX 750 and have a good profit, but depends on the market.
Right now it is not profitable. However, if you can buy the RX Vega 64 or Vega 32, it's a different story. You need to consider that GTX 750 it is almost free electricity because doesn't consume, in the other hand, Vega are expensive.
In the other hand, the most cost-efficient in terms of hashrate and power consumption, is the GTX 750 Ti. This is the best GPU you can buy if you want to mine Cryptonight (again, in terms os efficiency), but for example, in my country, this card is very expensive because is old and there are a few.
The realistic way is the RX 580, RX Vega 32 or RX Vega 64. Nvidia loses against that videocards today.
If you cannot buy an expensive videocard like I said before, then the best you can do is buy some GTX 750 and mining new CryptoNights coins / coins that doesn't have very much hashrate in the network.
You'll be struggling for mining monero with GTX 750, because you need a lot of them to make something, but yeah, it is worth if you can, for small miners.
Don't try to mine any other coin if you have cards with less than 4 GB. I only think now a few coins that can be mined efficiently with GPU and that could be Bitcore, EquiHash, EthHash and CryptoNight. Only the last of those algorithms it's worth mining with low-end GPU's or even CPU's.
I talk with personal experience, I bought 3 GTX 750, I have free electricity for them, and I mined a lof of different CryptoNight coins and yes, it was worth. Love these cards, you can do whatever you want to them and works like new product. Even I used them OC'ed and in summer, never any problem. I have it still but I'm not mining now, I used it 1 year with no rest, and works pretty well, even run games like new it was new cards.