How often should one change this? I assembled this computer about 4 years ago and never changed it yet, but my CPU temps are reaching ~90 now and sometimes feels laggy. Could it be because of the temps?
I think I applied arctic MX-4 but not sure. If I do need a new one, which should I get? (nothing too pricy, this pc will be fully replaced anyway in the next few years)

When you notice your temps have taken a dive and clearing out any dust from your heatsinks fails to alleviate the problem.

Most modern thermal compounds, as long as you didn't shoot for the stock stuff, or the cheap quality stuff, should be fine for as long as the component is functioning.
Its a non-problem 95% of the time in custom builds.

I would get King Arthur's opinion as well he is a good resource for custom builds here.

Yeah you're thermal throttling, that's why ur "lagging"
Just re apply a fresh paste after removing ur old residue

It's hot but it might not be paste. Have you given your PC a thorough dusting and made sure all fans are working?

I mean I guess I'm not a heavy user but I have never had to except when moving as I'll take out certain parts including taking off the heatsink.

No real increase in Temp even after several years.

I clean dust out regularly since I have a really bad case (it just gathers up in there so fast). I mean my computer is 75 degrees now in idle and I'm down to 50 fps in games I used to have 200+ in.

Can this happen suddenly? Because two days ago everything was fine and then yesterday all of a sudden everything started lagging.

If you're 75C at idle, you need to change the thermal compound on your CPU heatsink.

Clean the old compound offvery well, and apply new TC. THEN we can see if/what other problems you may have.

So another arctic mx-4 will be fine right? Only one in stock in the store available for pick-up today.

Are alcohol wipes included in these? They only sell 1l of isopropyl and I really don't want to buy that much since this is the only time I'll be using it

e: nvm found like 100 wipes of 70% isopropyl i had for disinfection

This post was edited by ImoK on Mar 8 2019 03:16am

Went and bought new paste, applied and now idle temps are ~35

Is there anything in particular I have to do? Like a waiting time before gaming or is it just bang on and it's done