Conclusion

Final Words 

Aside from a bit more performance in single-threaded scenarios and when the workload is on a handful of threads, the new XT is not going to bring massive gains at all. The new XT SKUs from AMD offer a notch more performance, and they are introduced at the original X model price series. So that's not a bad proposition, the 3900XT is now a super fast single-threaded performance leader. As mentioned in that first line, the challenge with the new XT processors is that they produce heat faster than the non-XT models, as fewer threads may now clock higher and faster, that requires voltage... and voltage = heat. You can tell as, at idle, temperatures are already a notch higher as this CPU wants to perform quickly and swiftly in single-threaded workloads. So even with LCS cooling, you're now looking at a 71 Degrees C temperature under load (which is fine). Please do make a note of this, the heat buildup under that heatspreader advances (jumps up) faster, ergo I would not recommend a heat pipe cooler for the 3800XT and 3900XT unless its uber-premium. You need some form of LCS cooling, keep that in mind, okay? 

Price and value

Gaming performance

Zen2 Matisse based processors make up for a lot of the losses in gaming compared to Intel. Combined with the respective platform, ZEN2 offers far more oomph compared to the previous two generations of Ryzen processors. There are mostly wins for Intel; there will be wins for AMD based on competing and price level matched processors. Only the fastest GPUs or lowest resolutions on the globe will show a difference in performance as, these days, a CPU is not a bottleneck, your GPU is. Ergo we use that GeForce RTX 2080 Ti (to be able to measure tangible differences). With a mainstream graphics card, it would be a much closer call to make.

DDR4 Memory

Memory compatibility should not and likely will not be an issue as long as you stick to recently released DIMMs. I'll keep repeating this, but there are some good Ryzen optimized kits out there. With Ryzen Generation 3 you can go higher in DDR4 clock frequency if you want to. Please check out our latest article on frequency and timings versus the effect on game performance. We advise that with up-to 3600 MHz and CL16 you are good to go, after that frequency value a 2:1 divider kicks in and that can have an effect on the Infinity Fabric bandwidth, thus inter-core CCX bandwidth. We see no reason for faster DDR4 memory anyways, it's expensive and does not bring in added performance, much like what you see on Intel platforms as well. We recommend a 3200 to 3600 MHz CL16 memory kit and, if you can find it cheap enough, go with CL14.

Energy efficiency

These processors are fabbed at 7nm; you may see some exceptional energy efficiency, the 105 Watts listed for the 3900XT was not necessarily something we could measure anywhere and thus remains relative, of course, that is amazing all by itself. Mind you; these are numbers at nominal load. The load values are excellent. Despite that, this processor series runs a notch faster, AMD stays within its Wattage / Voltage and TDP budget. They are merely redistributing voltage and frequency with lower thread counts. When we stressed all 12 cores, we sit in a 250 Watt power consumption range, that's for the entire PC. 

The conclusion

The 3900X versus the 3900XT is a bit harder to justify in performance. If you need that sharpest single-thread performance on a mega-core processor, then this ticks the right boxes. With a handful of threads, you're looking at a few percent more performance and, with all-core load, that difference simply is NIL. So for me to explain what the point of the 3900XT is, well, it is hard to say. The processor has to deal with faster heat build-up, you need to compensate for that effect by using an LCS cooling kit. No biggy, as with a 3900X, I would expect nothing less. You're sitting at just over 70 Degrees C under full 24-thread load, which is perfectly fine really. There isn't much left to tweak as we reached 4400 Mhz on all cores. We do expect that some lucky ones will reach 4500 MHz allcore. My advice, leave the processor at defaults really as the single turbo bins can reach almost 4.8 GHz! AMD did a great job maximizing performance on these processors, activating the fastest cores when you need them.

You can argue that AMD did most of the tweaking work for you. For gaming, you're good to go as, with any graphics card, just not the 1000 USD ones, the performance is there unless you want to squeeze out every bit of remaining performance, after QHD and UHD it's just not relevant anymore even to discuss. At 499 , the regular 3900X, however, has dropped in (street) price significantly, keep that in mind. But yes, AMD prices this product the same as they priced the 3900X last year. In the end, both the 3900X and 3900XT still is a fantastic sweet-spot processor for people that need many cores in demanding workloads like encoding or transcoding video. The choice between X and XT is just that, a choice. Is the XT the better processor? Well, that will depend on who you ask. It does fly a bit higher with single-threaded workloads. Would you ever notice the performance difference between the two models in real-world scenarios? We doubt that a little to be perfectly honest. But overall, this ZEN2 product is a feisty, capable one and worthy of a recommendation. That said, we think the 3900XT is a processor that will suit many. If you are building a high-end DIY PC and require a proper performing creator at a fair budget with the option to play games perfectly fine, well yes, this processor ticks quite a number of the right boxes. We do have to say though that, bang for buck wise, we still feel a 6-core 3600X or 8-core 3700X is the sweet spot proc to get. However, if you need a few more cores for that demanding workload of yours, slap a good LCS on this proc and your eyebrows will raise alongside the smile on your face. Small note that might sweeten the deal, the Ryzen series 3700X, 3800X, 3800 XT, 3900X, 3900XT and 3950 are bundled with a free key for Assassin’s Creed Valhalla.

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