I have a 8 gigs ddr3 2400
an intel 4670k at 4.3
and I am rocking a gtx 670
I need a decent gaming video card upgrade without breaking the bank. Right now on 1080, but would like hit 1440 when my monitor goes TU. it's 7 years old.
RX 580. It comes with 2 free games and most 580's can be had for $200 and LESS. On sale you can find 580's for as low as $160, with two free games at $60 value, that amounts to paying only $40 for your graphic card.
So you essentially buy 2 games, add $40 and you get a graphic card, that is a sweet deal. You have a choice of 3 new games as well, Resident Evil 2, Division 2, and Devil May Cry. All new, triple A $60 games.
I think for 1440p a cheap used 1070/1070ti would be as far as i would go.Would be pretty dang good for 1080p as well.I think the 8gb will be future proof too given you seem to be more about keeping a gpu for a VERY long time.Any titles you may play in the future that include RT will be bottlenecked by both the i5 and 8gb most likely.No point in the RT tax with a RTX card.
I do know for certain my i5 4460 and 8gb held back my 1070ti at both 1080p and a bit at 1440p as well.Given you got a oc i think a 1070 would be a perfect fit.People find them occasionally around $200 used.
What is your budget? I would probably go with an RX 580 or GTX 1660, but if you can spend more on other upgrades as well such as more ram and the 1440p monitor, then I would also consider higher cards if possible.