The Intel Core i9-7900X 10-core Skylake-X Processor Review
1080p Gaming Performance and Overclocking
Okay everyone, buckle up. With all of the debate surrounding 1080p gaming on high performance processors, we of course had to look at that with the Core i9-7900X. The results are… interesting
First, the 7900X is never faster than the 6950X in the gaming tests we ran, although it is able to match performance in Ashes, Deus Ex: Human Revolution, Ghost Recon Wildlands, and GTA V (mostly). However, take a look at Civ 6, Far Cry Primal, or even Hitman and Rise of the Tomb Raider: these show the new 7900X as slower than the 6950X in gaming, even with its substantial clock speed advantages. How? Remember back to this graph I showed you on thread-to-thread communication latency?
In a similar, but somewhat less substantial manner, the behavior we are seeing on Skylake-X with its longer LLC/L3 latencies, is an analog to the issues that concerned us with the Ryzen processor CCX implementation.
Obviously this is going to raise a lot of eyebrows and give the AMD fans a reason to poke fun at Intel, but the Core i9-7900X is still faster in this regard than the Ryzen 7 1800X in 7 of our 8 tested games. CPU architectures are complex, and the decision to use a mesh design for the intra-core communication was made for the Xeon product family, but there are clearly some interesting consequences for consumer workloads.
As we said in our Ryzen 7 review, as you increase the gaming resolutions above the 1080p mark, these deltas between ALL processors are going to be minimized. So, if you are a 4K gamer, or you plan to be one, any of these four CPUs is going to run splendidly.
Overclocking the Core i9-7900X
Though my time with the ASUS X299-Deluxe and the Core i9-7900X was short, I was able to get our sample overclocked to an impressive state. With a core voltage of 1.28v I was able to push all cores to a 4.6 GHz and run the system mostly stable.
However, temperatures at this point would spike to over 100C (!!) and level off in the mid-90C range, which was too hot for me to run for an extended period with a clear conscious, even with a Corsair H100i GTX as the cooler.
I eventually settled on a 4.5 GHz overclock on all cores and a Vcore of 1.24v, which allowed the system to stabilize around 83C with our cooling setup. Even that is going to be high for a lot of users, but the performance advantages of running all 10-cores at 4.5 GHz should be around 10-12% on heavily threaded applications.
We’ll dive more into this as time permits!