Overclocking

With the potential for a massive drop in all-core frequency from a manual overclock given the stock speed all-core boost sitting below 3.3GHz, we decided to play with PBO and automatic overclocking. We had a fair amount of headroom with our CPU cooler, which gives 360mm Asetek-made AIOs a run for their money despite only sporting a thick 240mm radiator and low-power version of the DDC pump. Doing nothing more than tweaking the automatic overclocking option in Ryzen Master, we saw the CPU hit 3.9GHz across most cores when under full load. This saw temperatures spike around 90 degrees, which is undeniably toasty, but the frequency is considerably higher than we'd expected.

Performance Analysis

As we suspected, applications that offer mediocre scaling suffered from the lower boosting frequencies across multiple cores and the 64-core CPU was slower in Adobe Premiere Pro, HandBrake and PCMark's photo editing test than its siblings. Even the overclock didn't help much, dropping the Premiere Pro export time by just 5 seconds.

Switch to more multi-threaded software and the CPU is stunning both at stock speed and when overclocked, sitting at 24,000 and well over 28,000 points in Cinebench R20, respectively - massive, massive scores. Our 2019 Blender test doesn't support this many cores, but we included it anyway. However, we've also added new Blender benchmarks based on v2.82 and these take full advantage of the Threadripper 3990X. The bmw27 benchmark sat at 31 seconds at stock speed compared to 46 seconds for the Threadripper 3970X. However, this fell to just 24 seconds when overclocked, pushing out cooling to its absolute limits. It's the only test we've run outside of Prime95 that saw our beastly EK MLC Phoenix radiator get warm to the touch. It was similar results in the rest of the blender tests, but with varying benefits from the overclock.

Games were reasonable too, with not much performance lost to its 3rd Gen siblings in Dota 2 and mostly matching them in Far Cry 5. However, we did see lower scores in some tests when overclocked, which makes us think that PBO and Automatic overclocking might be having some unintended affects. Similarly, the Time Spy score can also be put down to the lower frequencies across multiple cores under load, but this was another test to benefit from enabling AMD's automatic overclocking. The downside to that overclock, though, despite it coming straight out of Ryzen Master, is that power consumption for the system spiked at over 800W, maxing out our PSU. This is rather scary, so it's clear you'll need to do some investigating when it comes to overclocking. With similar or better cooling to us, AMD's tools are one option and mean you maintain that single-core boost. However, how much use is that to a potential customer of this CPU? Probably not much, but with our sample and cooling, 3.6-3.8GHz would be an easy target for a manual all-core overclock, and that's a big increase over the stock boost we saw of between 3-3.25GHz.

Conclusion

An all-rounder it is not, but the Ryzen Threadripper 3990X is not as dire outside of those all core-hammering multi-threaded workloads as AMD's previous desktop flagship, meaning you can sneak into an FPS during lunch hour between those hefty rendering sessions without losing too many frames. However, there are definitely areas where it doesn't just represent poor value, but is actually slower than cheaper CPUs. Even Intel's Core i9-10980XE and Core i9-9980XE were better options in Premiere Pro and HandBrake while offering significantly better performance in games, especially once overclocked.

However, all that is to miss the point of this CPU, which is for less than $4000/£3,500, you get mind-blowing desktop performance in software that can tap into those 128 threads. It's diabolically powerful for the cash and god only knows what AMD has in store later on in the Threadripper story. Intel might have some interesting options for gaming with 10th Gen CPUs, at the low-end too thanks to rumoured top-to-bottom Hyper-Threading enabled CPUs. However, at the high end, AMD's 3rd Gen Threadripper CPUs are utterly dominant in a huge array of tasks and while the Threadripper 3960X is by far the best allrounder, the Threadripper 3990X is the performance king when it comes to ultimate multi-threaded performance.