Keeping marketing checked by reality is part of the reason that technical media should exist: Part of the job is to filter out the adjectives and subjective language for consumers and get to the objective truth. Intel’s initial marketing deck contained a slide that suggested their new X-series CPUs could run 3-way or 4-way GPUs for 12K Gaming. Those are their exact words: "12K Gaming," supported by orange demarcation for the X-series, whereas it is implicitly not supported (in the slide) on the K-SKU desktop CPUs. Not to speak of how uncommon that resolution is, this also isn’t a real resolution. Regardless, we’re using this discussion of Intel’s "12K" claims as an opportunity to benchmark two x8 GPUs on a 7700K with two x16 GPUs on a 7900X, with some tests disabling cores and boosting clock. We have also received a statement from Intel to GamersNexus regarding the marketing language.
First of all, we need to define a few things: Intel’s version of 12K is not what you’d normally expect – in fact, it’s actually fewer pixels than 8K, so the naming is strongly misleading. Let’s break this down.
The RX 580, as we learned in the review process, isn’t all that different from its origins in the RX 480. The primary difference is in voltage and frequency afforded to the GPU proper, with other changes manifesting in maturation of the process over the past year of manufacturing. This means most optimizations are relegated to power (when idle – not under load) and frequency headroom. Gains on the new cards are not from anything fancy – just driving more power through under load.
Still, we were curious as to whether AMD’s drivers would permit cross-RX series multi-GPU. We decided to throw an MSI RX 580 Gaming X and MSI RX 480 Gaming X into a configuration to get things close, then see what’d happen.
The short of it is that this works. There is no explicit inhibitor built in to forbid users from running CrossFire with RX 400 and RX 500 series cards, as long as you’re doing 470/570 or 480/580. The GPU is the same, and frequency will just be matched to the slowest card, for the most part.
We think this will be a common use case, too. It makes sense: If you’re a current owner of an RX 480 and have been considering CrossFire (though we didn’t necessarily recommend it in previous content), the RX 580 will make the most sense for a secondary GPU. Well, primary, really – but you get the idea. The RX 400 series cards will see EOL and cease production in short order, if not already, which means that prices will stagnate and then skyrocket. That’s just what retailers do. Buying a 580, then, makes far more sense if dying for a CrossFire configuration, and you could even move the 580 to the top slot for best performance in single-GPU scenarios.
AMD's fanfare surrounding CrossFire with the RX 480s demanded a test of the configuration, and we decided to run the architecturally similar RX 470s through the same ringer. We only have two RX 470s presently in the lab, and they're not the same card – but we'll talk about how that impacts testing in a moment. The cards used are the Sapphire RX 470 Platinum Edition ($200) and the MSI RX 470 Gaming X, tested mostly in DirectX 11 and OpenGL titles, with some DirectX 12 Explicit Multi-GPU testing toward the end.
The benchmark runs a performance analysis of two CrossFire RX 470s versus a single RX 470, single RX 480, CrossFire RX 480s, and the latest GTX cards (1070, 1060). We're looking at framerate and CrossFire power draw here, with no thermal testing. Read our RX 470 review for in-depth thermal and frequency stability analysis (and overclocking).
AMD's panoply of RX 480 news announcements teased superior performance to the then-new GTX 1080 when paired in CrossFire. We decided to buy a second RX 480 8GB card for $240, put it into CrossFire with our sample that we reviewed, and validate those claims.
Multi-GPU configurations are tough to benchmark. We need to perform all the same thermal, noise, power, and FPS analysis as with other devices – but special attention must be paid to 1% and 0.1% low frame values, and more attention still paid toward plotting metrics versus time. Frequency, temperature, and fan RPM have some fluctuations that appear with multi-GPU configurations which are only truly visible when plotting versus time, rather than averaging a set of thousands of points of data.
In our performance review of CrossFire RX 480 8GB cards, we test FPS in Mirror's Edge, The Division, GTA V, and more, alongside temperature, noise, and power performance. We understand that thermals, noise, and power are sometimes less exciting to readers than raw FPS output, but would strongly recommend looking into our results for this benchmark – multi-GPU setups put greater emphasis on such testing. Some games show negative scaling, some positive, and some which are nearly unchanged. All of that below.
We moderate comments on a ~24~48 hour cycle. There will be some delay after submitting a comment.