Friday, July 29, 2016

CPU Lapping vs Delidding: One, The Other, or Both?

CPU lapping and CPU delidding are two things that can help with your CPU performance in terms of thermals, and thus, overclocking ability. The majority of computer users will have no need to perform either, but those of us who strive to squeeze every drop of performance out of our CPU's may want to try one, the other, or both. Today I want to give an explanation explain on what they are and what they can do.

CPU Lapping
Simply put, CPU lapping is the process of taking a CPU and making it perfectly flat. You may be thinking, "Isn't it already flat?". For the most part, it is. However, there are often times where it is not perfectly flat, and because of that, it can have an affect on your CPU performance.

First off, a CPU will be connected to some sort of heatsink in order to properly dissipate the heat it creates. If the surfaces of the CPU and the heatsink are perfectly flat, then the contact between the two will allow for the best heat transference possible. Yet, if the CPU, heatsink, or both, have surfaces that are not perfectly flat, then they may only be making some contact, allowing the CPU to retain a portion of the heat it is meant to get rid of through the heatsink. Generally, more heat to the CPU equals less performance.

Second, before one would perform CPU lapping, they would want to check if their surface is flat or not. An extremely easy way to do this is to take a metal ruler and check different areas on the CPU to see if it is evenly flat. If it is, then CPU lapping is unnecessary. The same can be done to check a heatsink.

The actual act of CPU lapping is relatively straightforward: Take sandpaper (you can use one type of grit or have differing grits for smoother results), place the sandpaper on a smooth surface like a table (taping it is a good idea), then proceed to move the CPU up-and-down on its surface over the sandpaper until the CPU has a reflective surface.

CPU lapping is meant to help bring down temperatures, and it can, but the amount it can depends on the severity of the CPU surface. From what I have read, it seems that most people get very little gains compared to the time and energy used to achieve those gains. I would say, on average, most people get around 1-2 degrees less on their temps.

CPU Delidding
Delidding a CPU is defined as taking off the lid--otherwise known as the IHS (Integrated Heat Spreader)--and replacing the thermal paste inside with a better grade of thermal paste.

This was not something that was always done as it was not until the Ivy Bridge generation of Intel CPU's that made this (somewhat) necessary. Prior to that generation, all "lids" were soldered on. For some reason, Intel decided to change this approach and use cheap thermal paste, causing worse heat transference.

The process of delidding can be done in a few ways. The most common is by use of a razer to carefully pry open the lid. More recently, a few companies have decided to produce and sell delidding tools that make it foolproof to perform this process: Rockit 88, der8auer, & Enter Setup.

I happened to pick up the Rockit 88 version, as it was the most inexpensive and the only one located in the USA. The der8auer version I believe was the first on the market, and is from Europe, but at least twice as much as the other options. The Enter Setup version is probably the cheapest choice if you happen to live in or near Europe.

On a side note, if you do happen to get the Rockit 88 delid tool, you have the option to also pick up the "re-lid" tool, which is meant to help to place the lid back on. I recommend not buying this additional tool as it should make little difference if you plan on putting the CPU immediately into a motherboard after delidding... 

If you have a 3D printer and want to make your own delid tool, here is a project that people have had success with: 3D Printer Delid Tool Project

Once the lid has been popped off, you will clean the small rectangular surface area that has the current thermal paste (which is probably solidified). Apply some new thermal paste and place the lid back on. The tricky part is that you will want to apply pressure to the lid so that it is completely flat. Most people who perform this procedure are ready to place the CPU into a motherboard and attach a heatsink, which helps keep it flat.

Again, from my readings, most people seem to notice a 5-10 degree drop in the average temperatures. This is a decent drop, and replacing factory thermal paste will often produce such results.

Is CPU Lapping/Delidding Important?
I would say that most people will have no need to really do either procedure. Even horrible temperatures would suggest issues elsewhere that need investigating. But it will matter to enthusiasts and overclockers. People who have the desire for the lowest temperatures at all times!

An enthusiast may just want this for bragging rights, but an overclocker will want to try these methods since lower temps can help achieve higher CPU overclocks. There is obviously no guarantee, and a stable overclock will largely be based on the binning of the CPU; but I can attest that lower temperatures definitely help to push a CPU further.

I guess if I was looking for the best temperatures possible, then a CPU lapping and delidding would be in order.

But I am a practical guy, and I actually just faced this situation recently on a new desktop with an i5 3570K. The CPU lapping seems easy enough to do, but for getting 1 degree less on my average temperatures, it is just a waste of my time. I have also heard that it can depreciate the resale value of a CPU compared to one that has not been lapped.

Instead, I opted to only do a delidding. I used the Rockit 88 delid tool as I did not want to harm anything with a razor. I then applied some thermal paste and placed the lid back on the CPU.

Was It Worth It?
I did end up buying the re-lid tool for Rockit 88, so I let my CPU sit overnight before inserting it into an ASUS P8Z77-V motherboard. My goal was to see if I could overclock the 3570K to at least 4.8GHz, so I attached a Thermaltake Water 2.0 Extreme AIO closed-loop solution. With the Thermaltake AIO running in silent mode, my temps stay in the low 30's.

While I soon realized my 3570K was an average overclocker, the combination of the delidding and the Thermaltake AIO allowed me to achieve a stable 4.9GHz overclock! For those of you familiar with the "legendary" i5 2500K, most people would claim a 2500K running at 5GHz could match a 3570K running at 4.8GHz. When using the benchmark in CPU-Z I was able to outperform an i7 4970K, and come close to reaching an i7 6700K.

Not bad for a CPU from 2012 that has no Hyper-Threading.

My foray into delidding was a successful one. It cost a bit of money due to the reason of not just using a razor (of which I have none on hand). And I completely avoided CPU lapping as it really seems to do so little. I mean, if the CPU is not relatively smooth to begin with, then that CPU needs to be returned to the manufacturer!

If you decide to try either method, I would advise watching some of the YouTube videos to get a better feel of what you need to. And if you do not try any of the techniques, rest assured that you are not suffering any great performance losses (unless you are an overclocker!).

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