7 year old RMx is a VERY good candidate for replacement. Especially since the RMx from 7 years ago did not have the same warranty OR life expectancy as an RMx from the last few years, but at 7 years old yours is likely right on the cusp of when Corsair made that change so you might have either a 7 or 10 year warranty model.
Do you own or have access to a volt meter you can use for testing the PSU?
With a Skylake system, which now would be about 8 years old, at first guess I'd say your motherboard would be the MOST likely culprit for an age related failure right now. But your graphics card could certainly be the guilty party. So, the PSU can be tested if you have, can get or have access to a volt meter, whether digital or analog, and I can provide you with instructions on the correct way to do that, but the motherboard and graphics card are pretty much process of elimination for the average person since there are few ways to actually test those for intermittent failures.
If you know somebody with another known good graphics card that might let you borrow it for testing, that might help to eliminate or convict the graphics card. You could also remove the graphics card and run off only the integrated graphics from the CPU however if the problem ONLY happens during heavy gaming, then that might not tell you much.
Motherboard is pretty much an "it's all that's left" type situation, after everything else has basically been eliminated.
Does this ONLY happen, EVER, while gaming, or have you had it happen at all when doing something other than gaming? Have you had this graphics card since it was new or did you buy it used at some point? How long have you had it and has it been working fine previously until just recently or has it always had the problem you are experiencing now since you installed it?