Power Consumption & The Verdict
Prior to any overclocking the 7800X consumed just 6% more power than the 7700K and these figures are based on the average consumption recorded in six games, so the 7800X certainly isn't being fully utilized here. With both CPUs overclocked the 7800X consumes 13% more power, again not a huge difference. It's interesting to note that while the 7800X often didn't see much in the way of added performance from the overclock, it did still increase consumption by 16%.
We saw some mixed results in the games tested and without even tallying them up it's clear that the Core i7-7800X was underwhelming. The 7700K clearly seems like the best option for gamers.
Before we did any tinkering, the 7700K was on average 11% faster than the 7800X across the 30 games tested for the minimum frame rate. Once overclocked that margin was reduced to 9% and summing up all 30 games this way, 7800X doesn't look too bad, despite being slower.
Note: The average performance figures are a little different here as the rounding works a little differently
Here's a look at the performance results from all games. The 7700K was 13% faster at the stock speeds when comparing the minimum performance in all the games tested. As you can see, Far Cry Primal and Dawn of War III were a problem for the 7800X while it also struggled in Hitman, Grand Theft Auto V, Civilization IV, Player Unknowns Battlegrounds and Doom.
Roughly half of the games tested saw little difference between the CPUs and surprisingly of those games we find quite a few that are CPU demanding. Titles such as Overwatch, Ashes of the Singularity, Battlefield 1 and to an extend F1 2016.
I suspect that some of you will be tempted to comment about how Cities: Skylines, Arma 3 and Planet Coaster should have been included because they are particularly CPU demanding, but that's not really true. All three games run horribly on quad-core chips when the action gets going and they still run horribly on a 6, 8 and 10 cores. Their limitations come from the game engine they are built on or just the coding in general. You will find much the same with games such as StarCraft 2 for example, which is why Ashes of the Singularity is so impressive from an engine standpoint.
Moving on, I get that these high-end desktop models aren't really meant to be 'gaming' CPUs but it's not unrealistic to expect that gamers with cash will be looking at Intel's Core-X lineup, particularly the 6-core 7800X. Given how well it clocks, the extreme memory bandwidth and the fact that this is Intel's premium desktop platform, you would be forgiven for thinking the 7800X would be superior to the 7700K, at least in the latest and greatest titles. Sadly, this just isn't the case -- far from it, in fact.
Given what we saw when comparing the Ryzen 5 1400 and 1600, we know that some of the games can make good use of 6-core CPUs. You could argue that the 7700K's superior IPC performance and higher frequency makes up for what it lacks in cores and this is why the 7800X wasn't able to show the kind of advantage you might have expected, but it goes beyond that.
That doesn't really explain why the 7800X was just flat out slow by comparison for quite a few of the games tested. The likely reason for this is down to Intel restructuring the cache hierarchy. Compared to the 7700K, the 7800X has quadrupled the L2 cache per core while the shared L3 has been reduced by just over 30% per core. It's believed these changes combined with the way this new cache works makes Skylake-X more suited for server-related tasks and less efficient when it comes to things such as gaming, and that's certainly what we're seeing here.
- Intel Core i7-7700K on Amazon
- Intel Core i7-7700K on Newegg
- Intel Core i7-7800X on Amazon
- Intel Core i7-7800X on Newegg
Had the Core i7-7800X beaten the 7700K, then we would have to weigh up costs and see if it would be worth investing in the more expensive platform. However, considering the results we recorded, that hardly seems necessary. If you're a gamer, you should get the 7700K or look to AMD's Ryzen lineup. Speaking of which, I'm keen to add the Ryzen 7 1700 to these results so I'll aim to do that by next week. Stay tuned.