Ryzen 9 3900X: performance analysis

As with our Ryzen 7 3700X review, we opted for a smaller number of games here that still provided a wide range of requirements, from relatively naive games that do the vast majority of their processing within a single thread to true modern masterpieces of engineering that scale well all the way to the 12 cores and 24 threads of the 3900X.

Amongst these titles, we've selected gameplay segments that often force lesser CPUs below the 60fps standard when running at high graphical settings, even on an RTX 2080 Ti. These sections come from both older games like Crysis 3 and newer ones like Kingdom Come Deliverance, and often involve a lot of on-screen action, AI and other challenges.

Assassin's Creed Odyssey

Assassin's Creed Odyssey plays well at its lower graphical settings even on mediocre hardware, but crank the settings to ultra high and you'll need considerable CPU and GPU power to get a smooth result. If you're CPU bottlenecked when playing this game you'll run into some nasty stutter, so we recommend employing a framerate limiter (such as the one built into RTSS) to guarantee regular frame-times.

Looking at the 1080p results where we're the most CPU-bound, the 3900X only offers a small two per cent advantage over the 3700X. Inspect the minimum frame-rates though, and it's a different story - we see a 28 per cent leap in the lowest one per cent times, which manifests as significantly less stutter and slowdowns during gameplay as you're almost never dropping below 60fps on the flagship AMD processor. Intel's Core i7 and Core i9 CPUs offer even better results than their AMD counterparts, with the 9900K leading the 3900X by 10 per cent and the 9700K beating the 3700X by 28 per cent, again looking at the lowest one per cent frame-rates rather than the average.

Battlefield 5

Here's another recent game that demands a lot from your processor, even in the Tirailleur war story we chose to benchmark. We actually noticed CPU bottlenecking while testing the RTX 2060 Super, even with the overclocked Core i7 8700K that normally lives in our GPU testing rig, so clearly there's a heavier CPU load here than we've seen in previous Battlefield titles.

We got slightly odd results here, with the Core i9 9900K and Ryzen 9 3900X actually performing worse by a small margin than their mid-tier counterparts due to random stutter. It's not until you move up to 1440p or 4K that things settle down and the CPU bottleneck is lessened, resulting in smoother frame-times overall. Regardless, the Intel Core processors show a significant advantage over the Ryzen family, with better averages and better worst one per cent scores across most data points.

Far Cry 5

Far Cry 5 came out last year and is built on the modern Dunia engine, but Ubisoft's engineers haven't opted to truly embrace modern CPUs just yet. A single thread seems to perform the bulk of the heavy lifting throughout the benchmark scene, making single-threaded performance the most critical factor in frame-rates and frame-times.

That helps the Intel Core processors hold a heavy advantage at 1080p, with the 9900K leading the 3900X by nearly 30 per cent and the 9700K beating the 3700X by nearly 25 per cent. Curiously, the 3700X doesn't drop as low as the 3900X, effectively tying the 9700K when it comes to worst one per cent frame-rates.

AMD Ryzen 9 3900X analysis

• Introduction, hardware breakdown, test system
• Gaming benchmarks: Assassin's Creed Odyssey, Battlefield 5, Far Cry 5 [This Page]
• Gaming benchmarks: Crysis 3, Metro Exodus, Kingdom Come Deliverance, The Witcher 3
• Gaming benchmarks: Ryzen vs Core - memory bandwidth analysis
• Ryzen 9 3900X: the Digital Foundry verdict