Saying its not very good is an understatement and more like one of the worst series ever sold by Thermaltake and words like god awful is not an overstatement
Any sort of upgrade to the PC without buying a new PSU might put the whole PC at risk of damage
IF you can overclock your cpu (to at least 4.5 GHz), it's worth upgrading some key compartments. Otherwise, it is better to get a new rig - even an used 7700k with a good motherboard will do. A 2700k at stock speed is too slow for current games at a decent resolution (not the one you currently use ).
These are the parts that you need to upgrade:
1) GPU: get an used 1080 (about 350$) or new 2070 (about 550)
2) Monitor: get a 1440p screen of 27 or 32" at least 120hz with freesync. Model depends on your budget!
3) PSU: my usual recommendation is Corsair HX or SF series, 600W or higher. They will last 10+ years.
I think currently the best balance between costs ad gaming experience is 1440p, and my suggestions are towards that setup.
new rig 2019:
Intel 9900k >5ghz | Asus Maximus XI Gene | Eisbaer 360 LT (custom loop in progress) | bequiet! Dark Base 700 white edition | Team group Nighthawk 16GB 4000mhz | MSI RTX 2070 Armor | Storage: Intel Optane 900p 280GB + Samsung 970 evo plus 1TB + WD Red 3TB | Corsair HX850i | Benq BL3200PT 1440p | 1Gbit ftth |
You dont need a 750 watt PSU for a system with a GTX 1060 thats more than double what the system will ever draw
A good 550 watt would be more than enough power so buy a quality PSU not the cheapest and bigest unit you can find
The Corsair RMx the Seasonic Foucs Plus and the EVGA G3 are all good options, if you dont mind semi modular there is the normal Seasonic Focus or the Corsair TX Gold
The CX750M is not all that great
Edit: dont know if you are in the US but here are newegg links