Radeon HD 4750 is a fast-middle-class GPU based on the 40nm variant of the Terascale 1 architecture.
It was released quite some time after Radeon HD 4730 and stirs from a 40nm chip (instead of 55nm). It's therefore related to Radeon HD 4770 as it offers 640 Shader Processing Units, 32 TMUs and 16 ROPs on a 128-bit memory interface of fast GDDR5. However, the central unit runs at 750MHz in Radeon HD 4770 while, on Radeon HD 4730, it's clocked at 730MHz. The operating memory clock runs at 800MHz on both.
Radeon HD 4750 can be addressed as a power optimized Radeon HD 4770, since it only consumes 75 Watt, while the latter is expected to consume up to 80 Watt.
Therefore, it's still faster than Radeon HD 4830 and should offer similar performance to Radeon HD 4770.
Today's modern games, will run from low detail to high detail. Only DirectX 11 games aren't supported.