Just casual gaming with like ultra graphics and dont care about high fps as I only play Singleplayer titles.What is the objective here? Better game settings? Better fps? Higher resolution? What resolution and Hz is your monitor?
Psu: Corsair RM750xCan't make any GPU recommendation without knowing the exact PSU.
CPU: I7 3770750W is the advertised wattage of the unit. What is the make and model of your PSU? How old is the unit in question? As for your specs, you should list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
If I were in your shoes, I'd avoid buying a GPU and instead invest on a brand new platform with a discrete GPU since your processor(and assumed current platform) is incapable of dealing with the GPU's listed above. You're going to get display but your GPU's will be limited in performance.
I think a 1070 would be the best option since any of the cards u mentioned earlier would be a bottleneck with the 3770 so u would get the same performance if u can find a used 1070 would be a good upgrade or maybe a 1080 but it would bottleneck a little.CPU: I7 3770
MOTHERBOARD: Gigabyte GA- B75M
Ram: 16 gigs crucial 1600mhz
Storage( Hdd): 1tb seagate barracuda
Storage ( Ssd): 256gb sk hynix Sc 311
Gpu: gtx 770
PSU: Corsair rm750x
Chassis: MACUBE 110
OS: Windows 10 pro
Monitor: (just a standard 60hz, but very nice visuals)
Psu: Corsair RM750x
RTX3050 would be more up to date and be about the same performance. RTX2060 as well.
Only reason to avoid the RX6600 would be its limitation to PCIe 8x.
When mixing old and new, bottlenecks aren't really to be concerned with. You know that a fast GPU would benefit from from a faster CPU when you are targeting frame rate. But in this case, if you prioritize graphics settings and resolution, then get the fastest GPU you are willing to pay for. You can always (and eventually should) upgrade the CPU.