Dude, you were right to try reducing Vram clocks. The Access violation error that you are getting is usually invoked by either System Ram clock too high, or more rarely by Vram clock too high. In my experience though, too high Vram clock usually results in the game just closing to desktop with no error logged or a 'Device Removed' error & crash. System ram clock too high will allways give the 'Access Violation' error with a BSOD.
Try lowering system ram clock by 100mhz at a time & testing. If using XMP profiles (automatic Ram OC), Switch back to default ram timings (Auto) & test.
Good luck whatever the case.
FYI 1 : I've had this error only once in my entire play time so far. I believe that the issue arose due to me manually updating the nvngx.dll (DLSS) from 3.1.x.x to the latest 3.5.10. After a file verify corrected the .dll library, I have had no issues.
FYI 2 : Regarding any stutter you may have, I lowered shadows to medium. Everything else on Epic (disabled motion blur in game option), & that's it. No more stutter & locked to 60fps (emphasis on 'locked') as my 55" Sony is 4k 60hz.
System is : I9 9900k @ 5.0ghz (360 Rad LC), EVGA FTW3 2080ti Hybrid LC @ 2055mhz GPU, 8200mhz Vram, 32gb ddr4 3100mhz @XMP trident RGB, Corsair 1000watt modular PSU. Sony 55" 4k 60hz HDR for display.
*** Point to note ***
My GPU Vram clock is overclocked by offset +1200mhz. This takes it from stock 7000mhz to 8200mhz. I have yet to have a game crash (WRC) with 'my' Vram this high, pointing at very good stability with regard to Vram speed / timings sensitivity. Hence why I have advised you to review your system Ram settings.