Review: AMD Ryzen 9 3900XT and Ryzen 7 3800XT

Introduction

AMD lifted the wraps off a trio of Ryzen XT processors last month. The new range comprises Ryzen 5 3600XT, Ryzen 7 3800XT and Ryzen 9 3900XT and will coexist with regular X-suffixed parts in the market for exactly a year now. In this review, we'll ascertain what makes them different, how much better they are than incumbent solutions, and then dole out practical buying advice. First off, the usual high-level table.

The XT models serve to increase the peak boost speed compared to their regular X counterparts. There's an extra 100MHz for both the Ryzen 9 3900XT and Ryzen 5 3600XT while AMD finds a further 200MHz boost frequency on the Ryzen 7 3800XT.

That sounds a lot like frequency massaging at the factory, which is readily achievable by setting those exact speeds in the BIOS. There is more to it than that, actually, as AMD uses a newer revision of 7nm process technology from foundry partner TSMC. The upshot is that XT-suffixed processors are materially different from any other Ryzens on the market.

A key benefit of improved process technology is the innate ability to push the voltage/frequency curve up a bit. This means one can typically run at marginally higher speeds at the same voltage or operate at the same frequency with a smidge less wattage. As AMD governs maximum stock performance by what is known as the Package Power Tracking (PPT), or socket power, which remains unchanged between X and XT parts at 142W, 120W, and 100W for the three chips in descending order, respectively, any extra frequency is solely from this enhanced curve.

Pragmatically, one ought to see only a little extra frequency when all cores are being run at full chat, thereby butting against the PPT limit. There's more scope to run at higher frequencies with fewer cores active as performance is less constrained by limiters. Typically, the larger gains are witnessed in applications that use one to four threads, rather than the whole lot, and speaks to light-load applications and gaming in particular - areas in which rival Intel is strongest.

These XT chips extract whatever low-hanging fruit is left on the frequency table by regular X parts. Even so, expect gains firmly in the single-digit percentages as there's no manifest change in any other performance-enhancing parameter.

It's worth knowing that this trio arrives at retail at the same suggested price as incumbent X models. That doesn't tell the whole story, however, as what's already in the market will naturally be discounted by retailers in the face of XT. We expect there to be as much as a 15 percent real-world premium for this trio, even though AMD pricing suggests otherwise. A second note is that Ryzen 9 3900XT and Ryzen 7 3800XT ship without the capable Wraith Prism coolers present in the 'X' boxes.

AMD reckons its providing an extra purchasing dimension rather than canniballising existing SKUs with the introduction of XT. You can, on paper, avail yourself of more frequency at the expense of a higher street price and lack of bundled coolers on Ryzen 7 and 9 - the choice is yours. Ryzen 5 3600XT, meanwhile, continues to ship with Wraith Spire v2.

As an aside, sweetening the deals on 3rd Gen Ryzen 7 and Ryzen 9 chips, AMD today announces that anyone purchasing these processors between July 7 and October 3, 2020 will be able to claim a copy of Assassin's Creed Valhalla, which is due to be released at the tail end of the year. Remember this applies to both X and XT CPUs.

Coming back on point, let's now see if the sum of the promised improvements come to pass as we run the Ryzen 9 3900XT and Ryzen 7 3800XT through the benchmark gauntlet.