AMD completely abandoned the idea of CrossFire support when it introduced its Navi lineup, but if you ever wondered how two Navi graphics cards would perform together, Uniko's Hardware has the answer for you. For the sake of science, the publication paired a Radeon RX 5600 XT together with the Radeon RX 5700.
In the old days, it was pretty common to run a multi-GPU setup. On some occasions, a single graphics card wasn't powerful enough to deliver an adequate gaming experience, and in other occasions, it was just more cost-effective to buy two cheaper graphics cards. Before AMD launched Navi last year, the chipmaker estimated that less than 1% of gamers still use a multi-GPU configuration. Therefore, the company decided to axe CrossFire support with Navi. If you look at it, it was a sound decision as it frees up resources for AMD to distribute elsewhere.
You can't run two Navi graphics cards in a CrossFire configuration. However, you can still achieve a similar effect using the explicit multi-GPU (mGPU) functionality, which is present in the DirectX 12 and Vulkan APIs. It's a flexible technology as you can mix and match different graphics cards from both AMD and Nvidia to your heart's desire.
There are a lot of modern games that leverage the DirectX 12 and Vulkan APIs. Nevertheless, it's up to the developer to decide whether it wants to support mGPU or not. Uniko's Hardware pointed out that Rise of the Tomb Raider and Strange Brigade accepted the mGPU setup without problems. However, Strange Brigade only works with DirectX 12 mode as the game would crash in Vulkan mode. Interestingly, Shadow of the Tomb Raider would crash instantly as soon as it opened. Triple-A titles, including Gears 5, Borderlands 3, Tom Clancy's Rainbow Six Siege and The Division 2 don't support mGPU.
Radeon RX 5600 XT and Radeon RX 5700 mGPU Benchmarks
The test platform was comprised of the latest Ryzen 7 3700X processor, ASRock X570 Taichi motherboard and a G.Skill Flare X DDR4-3200 16GB (2x8GB) memory kit overclocked to 3,600 MHz with a Cas Latency of 16. The graphics cards in question are the Asus Dual Radeon RX 5700 EVO OC Edition and Asus TUF Gaming X3 Radeon RX 5600 XT EVO.
On the software side, Uniko's Hardware is using Windows 10 with the November 2019 update (version 1909) and Radeon Software Adrenalin 2020 Edition 20.2.1. The publication performed the tests at the 1920 x 1080 resolution with Ultra settings in Strange Brigade and Very High settings in Rise of the Tomb Raider.
|Header Cell - Column 0||Radeon RX 5700||Radeon RX 5700 + Radeon Rx 5600 XT|
|3DMark Time Spy||8,508 points||13,342 points|
|3DMark Time Spy Graphics Score||8,271 points||14,156 points|
|Strange Brigade Average||138.6 FPS||228.8 FPS|
|Strange Brigade 1% Low||98 FPS||151.2 FPS|
|Rise of the Tomb Raider Average||116.9 FPS||191.3 FPS|
|Rise of the Tomb Raider 1% Low||87.4 FPS||111.5 FPS|
After enabling mGPU, the 3DMark Time Spy score jumped up by 56.8%. The real-world gaming results show performance improvements up to 65.1% and 63.6% in Strange Brigade and Rise of the Tomb Raider, respectively.
When it comes to power consumption, the sole Radeon RX 5700 draws up to 259.6W while the mGPU configuration pulls around 446.4W. That's a very significant 72% increase in power draw.
The performance uplift is there, but you won't be enjoying it as much since mGPU support is limited to a handful of games. And then there is also the money issue. The cheapest RX 5600 XT and RX 5700 sell for $275 and $295, respectively. In total, you're looking at a $570 investment. You can pick up a custom Nvidia GeForce RTX 2070 Super for $500 and likely get the same amount of performance at around half the power consumption.
Unless you've recently upgraded to a new graphics card and have an old one lying around, it's pointless to run a multi-GPU setup in this day and age. Even so, you'll still have to find a game that supports it, and that's not to mention having to put up with micro-stuttering.