Overclocking

This is the first Skylake-X CPU we've tested since our first toe-dip with the Core i9-7900X, which proved to be a far better overclocker than its predecessor, the Core i7-6950X, reaching a lofty 4.7GHz with some toasty temperatures and 4.6GHz as an everyday overclock. 

With fewer cores involved, we hoped that the Core i7-7800X might be able to squeeze out some extra megahertz, and we did indeed reach a healthy 4.8GHz with a vcore of 1.29V. This is a fantastic result, as it represents the highest frequency we've ever achieved with an HEDT processor and is a massive 400MHz higher than the Core i7-6850K, one of Intel's previous generation six-core CPUs. 

The fact it did this at a voltage that was tameable by a modest all-in-one liquid-cooler makes the Core i7-7800X quite attractive to those that want a couple of extra cores but don't want to miss out on the high-frequency advantages offered by Intel's K-series mainstream CPUs. 

Performance Analysis

The single-threaded advantage is still fairly clear for Intel compared to both AMD's Ryzen and Threadripper CPUs, with Intel enjoying most of the top spots. However, there are some interesting comparisons to be made with the Core i7-7800X. Firstly, the extra cache on offer from its predecessor, the Core i7-6850K - double if we're talking about L3 - leads to an advantage in some tests despite the slower frequency of the older CPU. This was most evident in Deus Ex, where the latter had a noticeable lead at stock speed that was only matched by the new CPU when it was overclocked.

A somewhat damning comparison, though, comes in PCMark 10's photo editing test, where the cheaper AMD Ryzen 5 1600X managed to better it at stock speed; this is a CPU that costs close to £100 less. This was a rare situation, though, as in HandBrake, Terragen 4, and Cinebench as well as most of the game tests, the Intel CPU was faster both at stock speed and usually gained an even bigger advantage once overclocked despite the two CPUs offering six cores and 12 threads. 

Compared to the Core i7-6850K, apart from a select few tests, the restructured cache of the Skylake-X architecture and higher frequencies sees the new CPU outperform the old CPU sometimes by significant margins. It had an impressive lead at stock speed in HandBrake and Terragen 4, for example, and this was even larger once overclocked. This is interesting for a couple of reasons. Firstly, you could argue that an upgrade would be worth it, especially if you use the CPU for work and time is money. Secondly, the Core i7-7800X is much cheaper than the Core i7-6850K and indeed the Core i7- 6800K were at launch, emphasising a gear shift in Intel's pricing that could well be thanks to AMD's efforts this year.

Conclusion

It's easy to get lost amongst the mass of CPU sockets, chipsets, and CPUs that have hit the shelves this year, and as a result of a huge amount of decent offerings from both Intel and AMD, the Core i7-7800X finds itself in somewhat uneasy territory despite excellent performance in most of our tests and generally justifying its price tag. 

The simple reason for this is that Intel will soon offer a very similar CPU, but on its upcoming and likely cheaper mainstream platform in the form of the Core i7-8700K. Both CPUs will have six cores and 12 threads, but while the Core i7-8700K will likely be more expensive, motherboards will eventually be cheaper, and the CPU will also sport a lot more L3 cache if the rumours are to be believed.

The Z370 platform is also rumoured to offer more PCIe lanes than Z270, further negating reasons to consider opting for the company's HEDT platform (which is still likely to offer a few more), so the Core i7-7800X faces an uncertain future, especially as there will be far more motherboard options, especially concerning form factors such as micro-ATX and mini-ITX, for the Core i7-8700K too, with the only advantages therefore being quad-channel memory support and a supposed additional four PCIe lanes - 28 compared to 24. 

That's all conjecture for now, but it's worth factoring into your equation nonetheless. However, should you be looking at Intel's X299 platform anyway and all other things aside, the Core i7-7800X is a great CPU with what appears to be a decent amount of overclocking headroom despite the fact that Intel isn't using solder with Skylake-X CPUs. It also has the measure of AMD's six-core Ryzen 5 CPUs and offers a massive advantage in multi-threaded tests compared to the Core i7-7700K despite costing just a few notes more.