Massive frame drops while gaming

[BladedTombstone]

I own an Alienware 17 r4 with a 1070, I’ve had it for about 5 years now and I didn’t receive it new, it was a refurb. For about a year now I’ll be playing a game and my frames will drop massively, and it’ll last upwards of a few minutes. I’ve done some looking around at temps and usages when it happens and I noticed that my cpu usage will spike up to high 90’s and sometimes 100 percent usage when this is happening. I’m wondering if I should try to re apply some thermal paste myself or if it’s worth the money to have someone do it for me. Just looking for your guys’ opinions on what to do. 

Side note: I even got one of those laptop fan stands to hopefully help with what I’ve been calling “thermal throttling” which is probably not the right term to be using.