Will this gtx 960 be compatible?

Solution
these things are standard, i would not worry. if parts are from the same (generally) time (meaning not like one is 10 years older) it will most likely work.
one thing to watch out for are cpu because sockets tend to change quick. but for psu, pci-e, sata, you are safe
these things are standard, i would not worry. if parts are from the same (generally) time (meaning not like one is 10 years older) it will most likely work.
one thing to watch out for are cpu because sockets tend to change quick. but for psu, pci-e, sata, you are safe
 
Solution
Intel Core i7 4770 (3.40 GHz)
16 GB DDR3

XFX TS 550W 80+ Bronze Certified ATX Power Supply
NVIDIA GeForce GT 620 2GB

upgrading to : EVGA 02G-P4-2966-KR GeForce GTX 960 Gaming 2GB 128-Bit GDDR5 PCI Express 3.0 HDCP Ready SLI Support SuperSC ACX 2.0+ Video Card