AMD Ryzen 9 3900XT review

The AMD Ryzen 9 3900X was released exactly a year ago today. And we loved it. Loads of cores and decent gaming performance made it one of our favorite CPUs, and cemented its place in our best CPU guide. On paper this brand new Ryzen 9 3900XT takes that impressive chip and squeezes just a little more power out of it. The base clocks are unchanged at 3.8GHz, but the Boost goes from 4.6GHz up to 4.7GHz. Yup, a whole 100MHz.

You may be wondering how AMD has managed to squeeze an extra 100MHz out of this chip, even if it is only at boost, and apparently it's down to a better understanding of the 7nm production process. There are no other changes, though. The core and thread counts are the same, the cache levels are unchanged, and there are no tweaks to the underlying architecture.

What is different, compared to the existing 3900X, is you don't get the Wraith Prism cooler with the 3900XT. So essentially you gain 100MHz to the Boost clock and lose a cooler for the trouble.

I'm a big fan of AMD's coolers, and have used them in plenty of builds without issue. While there is certainly an argument for the 3900XT being at the limit of what the Wraith Prism can handle, and that plenty of high-end builders will want to go down the AIO route for such a high-end chip, having the option of doing so is very different to being forced to. Of course this was true of the 16-core, 32-thread Ryzen 9 3950X, but that chip really does push what the Wraith can handle. I don't have the same feeling about the 3900XT.

The Ryzen 9 3900XT, like the 3900X before it, is a beast of a mainstream processor. 12 cores and 24 threads gives you lots of raw power if you're a content creator that needs to produce videos and/or dabble in some 3D rendering. The 3900XT chews through such workloads in a way few desktops processors can, and it really pulls ahead of Intel's finest in such tasks.

CPU benchmarks

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The only problem here is the 3900X, which really isn't that far behind. You're looking at a 4% difference in the video encoding test, and 3% in the multi-core result from Cinebench R20. It's good that the newer chip does represent some uplift in performance, but we would have like a bit more to offset the loss of the cooler.

For testing we used a Corsair iCue H115 RGB Pro XT all-in-one cooler to keep the chip chilled, and the 3900XT did manage to hit it's rated boost speed, topping out at 4.725GHz with the overall CPU temperature topping out at 79°C. It tends to hit its maximum frequency only very briefly though, and for more thread-conscious loads the chip operates at around 4.2GHz, depending on the workload. 

Gaming benchmarks

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The good news with the Zen 2 architecture is that it's a competitive chip in the gaming arena as well. It's true that Intel still has the overall lead, but the delta is slight, especially at higher resolutions. You haven't had to choose between productivity and gaming for a year now, and this is still very much the case here.

One thing of note here is that there's very little between the 3900XT and the 3800XT when it comes to gaming, as both have a surfeit of cores and threads for the vast majority of modern games. There are two ways of absorbing this information: either the $100 difference nets you nothing in terms of gaming, or more positively, there's no gaming trade off from having those extra cores when you do have some downtime. 

Speaking of ready cash, there's a bit of a problem for the 3900XT, and it's value for money. Where the 3600XT is basically a straight upgrade to the 3600X (and comes with the same cooler), and the 3800XT manages a reasonable upgrade over the chip it replaces, the 3900XT is definitely the least compelling of the 'new' chips. It's potentially slightly faster in some instances, but not really by enough to matter.

The other factor that works against the 3900XT, and indeed against all of these new chips, is that though there has been no official price drop from AMD for the 3900X, 3800X, and the 3600X, they can generally be picked up for less if you scout around a bit. 

In the case of the 3900XT, this is more keenly felt. The chip it is aiming to replace can be picked up for $419 (from Amazon right now, although plenty of retailers have it for similar price), and that chip comes with the Wraith Prism cooler. While you can hit higher clocks with an AIO, it'll still do you right for the vast majority of the time.

Which all adds up to make the 3900XT the least exciting of AMD's new XT chips. It isn't a bad processor, far from it, but this latest spin is not particularly interesting either. It arguably represents a drop in value compared to the chip it is replacing (due to the lack of cooler), and from a gaming perspective brings very little extra  performance to the table. If you've already got your mind set on serious cooling, and you need this many cores, then it's a consideration, but given the drop in price of the 3900X, we just don't see this as $80 well spent for what is ostensibly the same performance.

Then there's the spectre of Zen 3 that is set for release before the end of the year. It's often the case that there's something better just on the horizon, but AMD has proved that it isn't satisfied with small improvements with its Zen architecture, and so a lot is expected of Zen 3. 

With five or six months to go until that drops, is this really a good time to pick up a high-end Zen 2 chip? I'd personally rather wait. If you need to build now, then there are better value options to this either way, like the Ryzen 9 3900X for starters.