It is highly dependent on the model of GT 730 you have. The gddr3 versions are complete and utter trash and will not work well at all. The gddr5 versions or actually semi reasonable and can handle native and 2x on some games. Games that require higher GPU performance may suffer.
You basically want the gk208-400-A1 version since the Fermi version is bad and the other Kepler version is crippled by the ddr3 memory (yes not even gddr3). I used to use the gk208 card in my emulation machine (it was a gt 640, but the good gt 730 is a rebrand from this card) and it worked mostly fine using OpenGl in whatever dev version of Dolphin 5.0 I was on at the time. But I mainly play on Native, I prefer it. This was also paired with a good CPU (i5 4690k with a slight overclock).
You basically want the gk208-400-A1 version since the Fermi version is bad and the other Kepler version is crippled by the ddr3 memory (yes not even gddr3). I used to use the gk208 card in my emulation machine (it was a gt 640, but the good gt 730 is a rebrand from this card) and it worked mostly fine using OpenGl in whatever dev version of Dolphin 5.0 I was on at the time. But I mainly play on Native, I prefer it. This was also paired with a good CPU (i5 4690k with a slight overclock).