Question To polish or not to polish CPUs and coolers

[Kmpres_Japan]

When I built my last system back in 2008 various blogs said that I should wet-sand and polish the top surface of my CPU and the bottom surface of my heatsink to flatten and maximize the surface areas for best heat transfer. This I did to my Noctua NH-12 cooler using a piece of plate glass and a succession of sandpaper grits up to 6,000 if memory serves correctly. I declined to do this to my quad core CPU lest I get metal dust in the pins, but the system worked perfectly and has run very cool to this day.

I'm now building a replacement for that system using an Intel i5-13600K CPU and an updated Noctua NH-U12A cooler designed to fit the new LGA1700 ASUS Z790 Plus motherboard.

I've not heard much on the need to polish CPUs and coolers since 2008. Does this mean that polishing is no longer required? I should think that polishing would be more important with today's more power hungry chips than in the past.

Your thoughts?

 

[Lutfij]

Lapping is the term. I'd leave them alone. You void warranty doing so, btw. If you have hardware taht is dispensable, then you can go ahead but please be warned that if your lapping surface isn't 100% flat, then you will end up with uneven spots, which will in turn drive up your temps, which defeats the purpose of lapping in the first place.

 

[Eximo]

No need to do it. Just another way to shave a few degrees off the temperatures.

Not just about flattening it, but you are also removing material between the actual CPU and and heatsink.

There are no pins on Intel CPUs (for quite some time) and no Pins on AM5 AMD CPUs, so that should no longer be a concern.

More commonly people do liquid metal between the IHS and CPU, de-lidding. And some people also do lapping on top of that.

 

[geofelt]

My thought...
Not worth it.

 

[USAFRet]

Just another way to shave a few degrees off the temperatures.

If even that.

In addition, you'd have to get it flat. As in...flatter than it started as.
It is quite easy to make things worse.

 

[Eximo]

Agreed.

I've delidded a CPU only once, because there was very uneven heating of the cores. I did not use liquid metal, just high end thermal paste. Went from a difference of 8 or so degrees between the hottest core, down to about 3 degrees. Which turned my CPU from hitting the low mid 80s to only the high 70s under a full load with a rather large overclock. 7700k running at 5Ghz.

I recall JayzTwoCents had cooling problems that actually came from a very convex CPU heatspreader. Basically the corners were so high that good contact in the center wasn't happening. A lapping of the CPU only took care of that one. Was an Intel HEDT if I recall.

 

[Kmpres_Japan]

When I built my last system back in 2008 various blogs said that I should wet-sand and polish the top surface of my CPU and the bottom surface of my heatsink to flatten and maximize the surface areas for best heat transfer. This I did to my Noctua NH-12 cooler using a piece of plate glass and a succession of sandpaper grits up to 6,000 if memory serves correctly. I declined to do this to my quad core CPU lest I get metal dust in the pins, but the system worked perfectly and has run very cool to this day.

I'm now building a replacement for that system using an Intel i5-13600K CPU and an updated Noctua NH-U12A cooler designed to fit the new LGA1700 ASUS Z790 Plus motherboard.

I've not heard much on the need to polish CPUs and coolers since 2008. Does this mean that polishing is no longer required? I should think that polishing would be more important with today's more power hungry chips than in the past.

Your thoughts?

If even that.

In addition, you'd have to get it flat. As in...flatter than it started as.
It is quite easy to make things worse.

Thank you, everybody. When I lapped my last build 15 years ago it ran so quiet and cool I don't think it ever broke 45degC. Of course it was a 2.4GHz quad-core CPU running stock and I never bothered to overclock it. In all that time all I did to it was occasionally blow the dust off the fan blades.

Now I have a 125 watt 5.1GHz 14-core CPU that is reputed to run much hotter. I went with the i5 rather than an i7 or i9 CPU to avoid having to use a water cooler. I'm not into games but I do want to try some video editing. Also wanted to climb out of my cave as it were and get something a bit more up to date. The nice thing about this setup is that I can always upgrade to a faster CPU later on, assuming my new Noctua cooler is up to the task of cooling it. Maybe then I'll have to lap it as I did the last one.