Just looking for a decent PSU. Currently have a seasonic mII 80+ bronze. Would like to get a 80+ gold or platinum. At least 750w or maybe 800 if possible.
Corsair seems to have many PSUs like TX RM and AX. What are the differences and which one is the best?
The seasonic G-750 is a very good choice, a very reliable brand, a semi-modular design it hits all the marks. Although i do have to ask you if you really need that much power, unless you are doing 3+ SLI or crossfire ad a top range CPU you will very likely not even arrive at the 80% goldilocks zone.
Any PSU is most efficient at 50% load. https://en.wikipedia.org/wiki/80_Plus.
What hardware are you using? You'll be extremely surprised to find out that during gaming you don't draw more than 300-350W, and that's with a video card that has at least an 8 pin connector (it can deliver 150W) and a 6 pin connector (75W). Add that to what the PCI slot can provide (a maximum of 75W) and you get 150+75+75=300W.
Even if you plan to overclock, you cannot go past the amount of power that the physical connections can provide for the graphics card, and you might not even reach that because of BIOS limitations in the graphics card. The other component that needs a lot of power is the CPU, but that isn't really stressed when gaming.
Don't believe me? https://www.youtube.com/watch?v=LiWThqgFfI4
EDIT: Ignore what he is saying about efficiency, a 1000W PSU at 100% load and 80% efficiency will draw 1250W from the wall and deliver the rater power, the full 1000W.