Overclocking

We've seen 4.8GHz and 4.9GHz all-core overclocked from the Core i9-10900X and Core i9-10940X, respectively, which are both substantial increases on the all-core boost frequencies and also match or better both CPU's peak single-core boost frequencies, too - something that often can't be said for AMD. The best we could achieve in an hour or two of tweaking was 4.9GHz, although this needed 1.32V to get there. With fewer cores than the two more expensive Cascade Lake-X CPUs, things weren't quite as toasty, reaching the upper 80°C under load with liquid cooling, but with a 600MHz boost to the stock all-core boost frequency, it's a price we're happy to pay. 

Performance Analysis

The true kings of Adobe Premiere Pro are AMD's two 3rd Gen Ryzen Threadrippers and Intel's Core i9-10980XE, all of which sat comfortably under 80 seconds in our short 4K move export. The Core i9-10940X, with its 14 cores, sat a fair way behind but was much quicker than either the Ryzen 9 3950X or Threadripper 2950X. Dropping to 12 cores with the Core i9-10920X and the 2nd Gen Threadripper CPU was pretty much neck and neck, with the former a fair bit faster still than the Ryzen 9 3950X at stock speed and especially once overclocked. 

AMD is pretty dominant in HandBrake and only once overclocked did the Core i9-10920X become a viable option, matching the Ryzen 9 3900X. In short, if you do a lot of video encoding, AMD's top-end mainstream CPUs are far better value, and if you need more PCIe lanes or memory channels, the Threadripper 2950X is probably a better option. It is a similar situation in Cinebench, with the Threadriper 2950X offering more grunt at stock speed and when overclocked, while the Ryzen 9 3900X still offers better bang for your buck. However, the Threadripper 2920X was significantly slower so combined with its waning stock levels, is fading as a cheaper alternative.

Again, only once overclocked was the Core i9-10920X a match for the Threadripper 2950X in Blender, but Zen 2's prowess here is very evident. POV-Ray sat more in AMD's favour, with the Threadripper 2950X outstripping the Intel 12-core by noticeable amounts, but it took the Ryzen 9 3950X to see off the threat once the Intel CPU was overclocked. Dota 2 saw the best results yet from the three slower Intel HEDT CPUs, with the Core i9-10920X faster at stock and overclocked speeds than anything AMD could muster, Far Cry 5 wasn't as favourable with the Intel CPU again needing a hefty overclock to remain competitive, and even here, the Ryzen 9 3950X was more than a match. Civ VI performed well with similar results to the rest of the modern HEDT CPU line-up, with the 4.9GHz overclock helping to secure a near-top-spot result. Time Spy is still owned by AMD, claiming the top two spots with its Threadripper 3960X and Ryzen 9 3950X, but the Core i9-10920X wasn't far behind. Phew.

The overclock is clearly essential, but it comes with a drawback, which as we've seen on all other Cascade Lake-X CPUs, is power consumption. At stock speed, the peak power draw for the system was 352W, which was around 100W higher than the Ryzen 9 3950X. This rose to 517W once overclocked - less than the Threadripper 2950X's overclocked pull from the wall,  but more than 150W higher than the flagship mainstream Ryzen CPU.

Conclusion

There are two safe havens for the Core i9-10920X - Dota 2 and Adobe Premiere Pro, at least with our benchmarks. The former still has Intel as the top dog, but this isn't the same in all games as we can see in Far Cry 5. Premiere Pro saw the Intel CPU better every cheaper CPU, including the Ryzen 9 3950X and by a sizeable amount once overclocked, so if you're building a Premiere Pro rig, it does just about make for a compelling sub-£750 option - just - and matches the Threadripper 2950X, too.

Elsewhere, the difference between it and mainstream CPUs is often swinging in the wrong direction. The cheaper Ryzen 9 3900X was much quicker at stock speed and the Ryzen 9 3950X a match once the Intel CPU was overclocked in HandBrake, with the same true in PC Mark 10's image editing test. Cinebench is mostly an AMD whitewash, but as we've seen, doesn't tell the whole story. In terms of core counts, the Intel CPU was a match in Blender and POV-Ray, but the problem is AMD isn't equal on price with the Ryzen 9 3900X costing £250 less.

As we suspected, the Core i9-10920X isn't as interesting as the Core i9-10940X, but is more competitive than the Core i9-10900X. Unfortunately, while the massive price cuts have allowed Intel to stay afloat, that competitiveness is extremely niche. If you were building an all-rounder, the Ryzen 9 3950X is a far better option, but the Threadripper 2950X is rarely a better buy, especially once you factor in more expensive X399 motherboards and as our own testing has shown, even cheap X299 motherboards can handle reasonable overclocks on these CPUs. While the Core i9-10940X just scraped an award for some select use cases, we sadly can't quite stretch to the same for the Core i9-10920X, unless you absolutely must have more PCIe lanes and/or memory channels than AMD's X570 platform provides and need something between that and TRX40. In all other situations with Intel's new 12-core HEDT CPU, its price cuts haven't been quite aggressive enough.