Best CPU for 1440p

[mtishi]

Budget (including currency): $500 AUD

Country: Australia

Games, programs or workloads that it will be used for: Mostly AAA games (E-sports games already get 165fps+)

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at, etc): 

I upgraded my old Ryzen 5 2600 + RX570 build to a new build with a 6700XT but kept the R5 2600. I upgraded my monitor from a 1080p 75hz to 1440p 165hz and from what I can tell the CPU is very much bottlenecking fps. My question is, should I upgrade to a 3600 or a 5600X? I know at 1440p the GPU is more important so I won't get a massive performance gain by going with the 5600X, but I'm not sure if this is how it works but when AMD's FidelityFX Super Resolution is released, could I play at 1080p upscaled and get that huge performance boost by going with the 5600X, or should I go with the 3600 or stick with the 2600 for now?

[Tech87]

You would definitely notice an increase in fps by going from 2600 to 3600 and again to 5600x.

I would say to buy the best cpu you can afford, as it will last you longer overall.

[Brooksie359]

If you are going to upgrade then get the 5600x no point in upgrading if you are just going to get the 3600. I mean the 3600 is objectively faster but not enough to justify the price compared to the 5600x which is significant faster. Thats just my personal opinion. Also you could keep the 5600x for longer which will save you money in the long run.