Overclocking the Intel Core i9-7900X X-series Processor

We have finally gotten some time to spend with the new Intel Core i9-7900X, which is a 10-core 20-thread CPU built to be used with the new X299 chipset and motherboard platform. Is this $1000 3.3GHz to 4.3GHz CPU good for overclocking beyond stock? Overclocking the 7900X takes a good bit of cooling, and then a little more for really pushing it hard.


Motherboard Power & Heat

So there has been a lot of talk about the Intel X299 platform being gimped in terms of power design across the board. That is not what I have found here at all. That however does not suggest that the X299 platform is not power hungry and require very good cooling. You will want to have a case airflow in mind if you are building a new High End Desktop (HEDT) system. The X299 is not for inexperienced system builder or for someone looking for a quick system build.

The video below is 4 minutes long and will show you how we were testing and what we are basing our conclusions on. I have done this testing on three X299 motherboards now, and I have not found issue with motherboard power overall.

The video above was shot with the MSI X299 SLI PLUS system that we have used for all the testing shown here.

I never once saw a "problem" with power delivery on this motherboard, and I did not see an "issue" with heat as well.

The heatsinks look to be working as those should. And while I would not suggest that the X299 SLI PLUS has a "robust" cooling system, it will very much do the job it needs to do if it is given the airflow that is needed. Also, it is a big plus in my book that this particular motherboard has its power component cooling fixed with screws down on the motherboard. If you have an X299 motherboard that uses pushpin-type mounts, those could be a problem. Those heatsinks fixed in that manner are notorious for getting bumped and moved around, and after that happens it is very likely that those heatsinks are not doing the best job that those could.

I know others have said that an additional ATX 4-pin 12v power header is needed on these motherboards. In my experience, working with water cooling, you are going to "hit the wall" in terms of dissipating CPU heat a long time before you will need the additional power delivery. Now an additional 4-pin 12v may very well be needed once you leave the realm of water or air cooling on the X299 platform, and quite frankly, that would not surprise me at all, in fact I would suggest that it will be needed. Also I think that some of the high-heat temperatures that we have seen reported on the 8-pin 12v ATX lead are impacted by heat being generated by the motherboard power components. I do think that if you are not taking your time and simply "jacking" voltage trying to get a quick overclock on the 7900X could cause issues here.

Turn Off the Fan

One thing we have done here for years while reviewing motherboards is that we have turned off that 120mm fan you see in the video, just to see what happens. In fact for a number of years, it was our go-to test for just how beefy a motherboard was. Not every motherboard is up to running 100% full load with zero airflow across the motherboard. And as you know, this is not a something you should be doing anyway....as its stupid. Its bad for your entire system to run a computer in a "hot box."

Even on our open test bench, with an ambient temperature of around 75F, this X299 platform does not last for long in terms of operating with no airflow.

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The two pictures above show the tempertures the MSI X299 SLI PLUS failed at with no airflow. The first picture at 72C/161F is the bottom of the motherboard under the power components with no airflow across the board, and the second picture at 67C/153F is the top of the heatsink. Keep in mind this is on an open-air testbench, so I would suggest you could hit these temperatures in a case rather quickly and cause you system failures if you are not cooling the entire system properly.

The Bottom Line

First and foremost, I do not think there is anything "wrong" with the Intel X299 platform in terms of power. The X299 platform is an HEDT system and the fact is that it needs to be treated as such. If you are a computer hardware enthusiast and want to overclock the 7900X (or lesser HEDT processors) you need to simply do a very good job of tweaking your system. I would suggest that every tenth of a volt makes a difference. We have been spoiled in recent years by "set it and forget" UEFI tweaks and preset profiles in those UEFI. That does not seem to be the case with the X299 and CPUs with more cores than 4. You are going to need to get your hands dirty and get into the UEFI and pay attention to your settings with a level of granularity that we are likely not used to. That said, it has been fun working on this needed level again.

In terms of motherboard cooling solutions, I am going to suggest that you buy a motherboard with a fixed heatsink solution. It also might not be a bad idea to go back and reseat those heatsinks with high quality TIMs as well. I am not saying that is needed, but it surely can't hurt. Also, remember I have told you I have worked with three X299 motherboards, and all have yielded somewhat different overclocking results. If you are going to buy an X299 motherboard, I would highly suggest that you not buy a specific model without first reading a review of that motherboard from a enthusiast website you trust. And I would suggest that you make sure that website looks into the cooling solution and delve somewhat into power delivery while overclocking. The differences I have seen in overclocking seem to be more UEFI based rather than hardware based. We will see.

That all said, I do think the X299 motherboard platform is getting near its limits in terms of enthusiast overclocking. Beyond air and water cooling your CPU, I do not think the X299 platform will show to be a long term stable solution. If you are going to build an HEDT X299 system, you need to be on your game in terms of UEFI tweaking and system cooling. If you do that you can build a monster Intel 10-C/20-T box if you want to.


Below again are our system components listed with commission links. We do appreciate your support and using these commission links helps keep HardOCP funded. You can support HardOCP on Patreon as well, for as little as a dollar a month.

We used the MSI X299 MSI Plus motherboard for our testing. It is currently in retail at Newegg for $260, and at Amazon for $261 with Prime Shipping. The Intel Core i9-7900X is listed for $1030 at Newegg, and $1062 at Amazon, but good luck finding those in stock.

We are also using 32GB of Corsair (CMK32GX4M4B3600C18) using its XMP profile at 3600MHz.