I play on a 5 year old laptop and apart from a bit slower loading times everything runs smoothly.
If you're having issues maybe it's time to upgrade the IBM5150.
I'm very passive when it comes to rivens. I don't actively hunt for them
If I get one for a weapon I like I might use it and roll if needed depending on disposition.
The rest get merged.
In duviri:
Status spread
Heat damage
Toxin on 3rd hit
3 hits and the group drops.
Bonus for cold aoe damage to enemies with cold status and ms per decree, the enemy can't even respond then.