Help me choose best GPU for my system

[viki_slash]

Help me choose GPU for my system.
I have

Intel Xeon x5365 3.0ghz quad core
8gb DDR2 ECC Fully Buffered Ram
750 Watts PSU

Here are some options for GPU and the price i am getting these GPUs, as i am confused,
Geforce GTX 275 (30 bucks), Radeon HD 4870 (35 Bucks), Radeon HD 7770 (60 bucks), Radeon HD 6790 (70 bucks), Radeon HD 6850 (70 bucks).

Also wanna ask that can GTX 275 and Radeon HD 4870 run Mortal Kombat X using dxcpl, as these two GPUs are DX10.

 

[mattbar]

http://www.videocardbenchmark.net/high_end_gpus.html

Geforce GTX 275 (30 bucks), 1228
Radeon HD 4870 (35 Bucks), 1376
Radeon HD 7770 (60 bucks), 2179
Radeon HD 6850 (70 bucks). 2246
Radeon HD 6790 (70 bucks), 3477
I would go for a more expensive video card at ~150$. I just bought a 1050 ti which scores a 5,976. It's gets better fps than my 770 gtx. My old 550 ti has trouble getting decent fps is games over 5 years old & it scores a 1,925. I would suggest the Radeon HD 6790. It does suck that it is the more expensive option but the other options are certainly too slow for many games.

https://steamcommunity.com/app/307780/discussions/0/618459405718933335/
mortal kombat x can be launched in dx9 so the game does support it although with graphical glitches on forest map and possibly some others. I do not know if they are fast enough to get good fps in the game though.