Improving the Thermal Performance of the Intel Kaby Lake CPU
With the introduction of the Intel Kaby Lake processors and Intel Z270 chipset, unprecedented overclocking became the norm. The new processors easily hit a core speed of 5.0GHz with little more than CPU core voltage tweaking. This overclocking performance increase came with a price tag. The Kaby Lake processor runs significantly hotter than previous generation processors, a seeming reversal in temperature trends from previous generation Intel CPUs. At stock settings, the individual cores in the CPU were recording in testing at hitting up to 65C - and that's with a high performance water loop cooling the processor. Per reports from various enthusiasts sites, Intel used inferior TIM (thermal interface material) in between the CPU die and underside of the CPU heat spreader, leading to increased temperatures when compared with previous CPU generations (in particular Skylake). This temperature increase did not affect overclocking much since the CPU will hit 5.0GHz speed easily, but does impact the means necessary to hit those performance levels.
Like with the previous generation Haswell CPUs, a few of the more adventurous enthusiasts used known methods in an attempt to address the heat concerns of the Kaby Lake processor be delidding the processor. Unlike in the initial days of the Haswell processor, the delidding process is much more stream-lined with the availability of delidding kits from several vendors. The delidding process still involves physically removing the heat spreader from the CPU, and exposing the CPU die. However, instead of cooling the die directly, the "safer" approach is to clean the die and underside of the heat spreader, apply new TIM (thermal interface material), and re-affix the heat spreader to the CPU. Going this route instead of direct-die cooling is considered safer because no additional or exotic support mechanisms are needed to keep the CPU cooler from crushing your precious die. However, calling it safe is a bit of an over-statement, you are physically separating the heat spreader from the CPU surface and voiding your CPU warranty at the same time. Although if that was a concern, you probably wouldn't be reading this article in the first place.
However you choose to approach the process, the first step is separating the heat spreader from the processor PCB. The heat spreader is mounted to the PCB using an RTV-style adhesive ensuring a secure seal, protecting the fragile processor die from outside contaminants and influences. There are several ways to remove the heat spreader including using a manufactured delidding tool, the razor blade method, and the vise method. With all methods, you are attempting to separate the CPU PCB from the heat spreader without damaging the CPU die or components on the top or bottom sides of the CPU PCB.
Razor Blade Method
The razor blade method involves using a double-edged razor blade to cut through the RTV material fixing the heat spreader in place, gently prying the heat spreader from the CPU PCB's surface. You carefully work the blade very carefully under all four corners of the heat spreader to weaken the RTV bond and slowly pry the heat spreader up off of the CPU's surface. This method has many potential pitfalls though. One of the largest is the possibility of cutting into the CPU PCB surface while attempting to cut through the RTV holding the heat spreader in place. Another pitfall to avoid with this method is the possibility of cutting through the circuits along to the right and left of the CPU die. This is more likely to occur if you attempt to insert the blade too far underneath the heat spreader while attempting to cut through the RTV.
The vise method involves locking the CPU in place by the heat spreader in a bench vise and using a rubber mallet to forcibly remove the CPU PCB from the heat spreader. You basically place a wood block against the edge of the CPU PCB and lightly tap the wood block until you notice separation between the CPU PCB and the heat spreader. While this method seems much more prone to CPU destruction than the razor blade method, it is actually a much safer method and much less prone to pitfalls than the razor blade method. However, you do have to fix your processor's heat spreader in a vise. If you would like more details on this method, you can see our Haswell delidding article here.
Delidding Tool Method
While none of the methods can be considered 100% safe, using one of the commercially available delidding tools removes alot of the guess work and fudge factor inherent to the other methods. No matter which vendor's tool you choose to purchase, delidding the processor is as simple as placing the CPU into the device, locking it in place, and turning a screw which exerts sideways force to the heat spreader to pop it off. The mechanism securing the CPU ensures the the heat spreader does not travel too far once detached, minimizing the possibility of damage to the processor die or PCB top-mounted circuitry.
Courtesy of RockIt Cool
Courtesy of RockIt Cool
For this endeavor, we chose to use the RockIt 88 delidding tool, purchased from RockIt Cool along with their LGA1150 re-lid kit because of their location in the US to cut down on shipping charges as well as the good reviews their product has gotten. In addition to the RockIt 88 tool, we used Coollaboratory Liquid Ultra thermal compound for the interface layer between the processor die and heat spreader, and black RTV adhesive to fix the heat spreader to the processor PCB surface.