Date: Wednesday, February 15, 2017
This is our latest update and results article in a saga of delidding and relidding Intel's latest Kaby Lake CPUs. This article comes a couple of weeks after we purchased an Intel Core i5-7600K from Amazon for $239.99. Intel has sampled HardOCP no processors, so this processor is just like one you might purchase yourself. Of course, as we have found with the Intel Core i7-7700K, your overclocking mileage may vary. This is the only 7600K we have purchased, and it has done quite well. This 7600K in its fully stock form would run 5GHz/3600MHz at 1.35v vCore with water cooling, which is certainly a great thing, but we wanted to see how far we could push it.
Our previous articles is this series is linked below.
Below you can see my very sloppy job done with reseating the IHS. However it worked just fine and it gave us a decreased CPU package temperatures of 13C under a full RealBench load. I am still looking for a smaller "nozzle" to lay down a cleaner and smaller bead of RTV silicone.
Thermalright and HardOCP have a fairly long history, simply for the fact that it has produced some of the best performing and cost-efficient CPU air coolers for many years. Given that, I reached out to Thermalright for a new HSF (HeatSink and Fan) to test our 7600K with. Many of our HardForum members asked that we gave 7600K overclocking a go on air rather than water, and that is understandable given that many 7600K users are looking for a more affordable solution. The Thermalright True Spirit 140 Direct that we used here today is $47 with Prime Shipping.
At this time I have the ASUS ROG Strix Z270I Gaming ITX form factor motherboard on the test bench being reviewed, so I decided to give it a go and see what our results were. Keep in mind since we are using a different motherboard than we were using previously, we can't really call those "exactly" comparable in terms of voltage and temps, but we are still very much "in the ballpark" when discussing cross-platform results. First and foremost, under water, we had to use the same clocks and voltages for our overclocking attempts that we did on the GIGABYTE Z270X Gaming 9 (review coming soon), so I am good with comparing results for conversation here.
Below are a series of pictures I took during the Thermalright True Spirit 140 Direct HSF install. I did find that the M.2 SSD heatsink that ASUS uses on this motherboard prevented the install of the HSF properly. While I do not have a definitive answer on this yet, I do think that Thermalright is "outside of the spec" here rather than ASUS, but we will hash that out in the HSF review.
You might also notice above in the pictures that the Thermalright TS140D comes with a shim-type device that fits down over the CPU substrate. The purpose of this is to alleviate pressure from the HSF bending the edges of the CPU substrate up. Seems like a good idea for long-term usage, but we did not use it because of my fat-fingering of the RTV during the relid process, and I did not want to possibly damage the CPU while removing the RTV adhesive.
To be succinct, as you might have been tipped off by the Sharpie notations on the CPU picture above, under water we needed a 1.40v vCore to get our 7600K stable at 5.1GHz with a 3600MHz memory clock using our Corsair Vengeance LPX 3600MHz RAM.
Using the Thermalright True Spirit 140 Direct we had much better results than I would have guessed. I only had to increase our 7600K's vCore to 1.41v in the UEFI in order to get 100% stability under RealBench v2.44 for a full 24 hours. This does equate to an actual measured vCore of 1.408v to 1.428v under load.
So what is the actual comparison in terms of temperatures under RealBench?
7600K 5.1GHz/3600MHz Water Cooled Temperatures
68C Package Temp - 69-72-71-74 Per Core Temps
7600K 5.1GHz/3600MHz Air Cooled Temperatures
74C Package Temp - 74-77-79-78 Per Core Temps
Finally we wanted to see what results we would get using Prime95. We do not use it anymore for long term stability testing because I do not see it as a "real" desktop workload as it introduced large AVX instruction set workloads. That said, I do not like to downclock the AVX either (although you can do that on new Z270 ASUS motherboards), and I wanted to see how our 7600K would hold up under air cooling. I shot a bit of video of our system working at 5.1GHz/3600MHz under air cooling while running Prime95. And its got pretty lights and it gets 4C hotter!
There is no doubt that an enthusiast wanting to get to that 5GHz milestone can do it with an Intel Core i5-7600K and air cooling if you choose your components wisely. Surely the Silicon Lottery always comes into play, but the 7600K processors seem to be much more successful at 5GHz with high memory clocks than the HyperThreaded-laden 7700K. And the fact of the matter is that most folks overclocking for desktop or VR gaming don't really give a damn about HyperThreading anyway.