CPU IHS refers to the instruction set architecture used by the processor.
CPU IHS refers to the instruction set architecture used by the processor.
I have built many PC's over the years, and I have never bothered trying to lap a IHS... I have lapped waterblocks, I have delidded CPU's, but I have never lapped one. It can be something fun to try, but honestly, seeing as there is no reason to do it, why bother? Especially with AMD where you can easily bend or break pins. On Intel at least there is almost nothing you can do to hurt the chip, AMD is not the same. There isn't really much your missing out on here. All you need is a piece of glass, multiple different stages of sandpaper up to ~3000 grit, and some water. You just wet sand it until its flat. Honestly, from experience doing waterblocks, its a massive PITA and your wrist will hurt for days after doing it. Honestly I would just not bother for all the reasons I listed, especially since your chip is already very cool. If anything, you could make it worse... IHS's are not flat, but heatsinks are not flat either; this is all on purpose. Sometimes an IHS or a heatsink will end up a little out of spec, and that is when lapping may help because its tooooo much not flat and causes bad contact. Sure seems like your IHS and whatever heatsink you have really like eachother. If you go and make your IHS flat, you may actually hurt thermal performance.
If your only at 70c, the potential benefits are not worth the potential losses. Honestly, at 70c under load, there is no reason to do anything. Just enjoy the PC as is, no need to be wasteful and buy more stuff just to buy more stuff. 70c is very, very cool... I run a full custom loop, and when I am in games I see CPU temps of mid 60's and that is great... your saying in 100% load your only seeing a few degrees more, so in games your likely in the 50's to potentially low 60's. Your already 15-20c cooler then you need to be, no reason spending money and bring a blind consumer at this point, your already winning.
For a fully loaded synthetic scenario, I anticipate high performance around the upper 70s at stock speeds during cooling, possibly reaching the high 80s based on OC, voltage, and chip quality. However, as someone familiar with the field, there’s a chance it could be slightly off. Generally, most chips maintain around 85°C under synthetic load, which isn’t unusual, though achieving true 100% load in a real test is rare. My CPU performs in the mid-80s during stress tests, even with strong water cooling. In games, it tends to sit in the mid-60s, which feels solid for the processor.
It's a technique most people no longer practice. Achieving that perfect mirror finish requires patience. Begin with 200 grit wet sanding paper, then progress through 400, 600, 800, 1000, 1500, and finally 2000 grit. You'll usually find the necessary supplies at an automotive parts store near you in the pain section. Start with the coarser grades until the surface resembles copper, ensuring it's flat. (AMD IHS is concave; edges will appear copper before the center.) If your cooler has exposed heat pipes meant to connect to the heat sink, minimize removal beginning around 1000 grit. Once you reach the machined flat mirror, tape it to the table and secure the paper on the mirror. For a smoother finish, use a figure-8 motion with water—dry it thoroughly. Tip: As you move to finer grits, the CPU plate will glide easily, reducing the need for heavy pressure. You're already level from the lower grits; just focus on polishing. The mirror will start to shine well at 1500, and many reach a finish around 2000. For those eager for a quick crash course, a lap tutorial is available.