Run a memtest. Graphics cards usually crash badly when given invalid data, which can happen sporadically if you have bad RAM.
If memtest shows a specific memory region as failing, swap out sticks to check which it is, and buy a new one. (Or if you're on a tight budget, you can disable that region with kernel boot options.)
If memtest gives errors in lots of places, might be a bad overclock. Loosen timings or give it more voltage.
> If memtest shows a specific memory region as failing, swap out sticks to check which it is, and buy a new one. (Or if you're on a tight budget, you can disable that region with kernel boot options.)
Honestly, I'd always do that as the first option. In most cases you can still get years of life out of that stick of ram (but do check regularly, like after a week and then double the interval every time if it didn't get worse).
If memtest shows a specific memory region as failing, swap out sticks to check which it is, and buy a new one. (Or if you're on a tight budget, you can disable that region with kernel boot options.)
If memtest gives errors in lots of places, might be a bad overclock. Loosen timings or give it more voltage.