Value and Conclusion

Let's deal with the elephant in the room first. By deciding to go CrossFire, you're essentially defeating the purpose of the Radeon R9 Nano (SFF, ITX builds), and so, the next most appropriate build environment is a compact (cube-shaped/pedestal) micro-ATX case where you'd want to take advantage of the compactness of these cards for better air-flow and cable-management.

The R9 Nano established itself as the go-to card for premium SFF builds, and in its 2-way CrossFire setup, it serves up decent levels of performance upscaling on games that can take advantage of CrossFire. The single R9 Nano wasn't unfit for 4K Ultra HD, but it wasn't the perfect card for it either, with the R9 Fury X and GTX 980 Ti offering far better performance at the same price, albeit with much larger form-factors. The R9 Nano CrossFire, however, offers incredible 4K Ultra HD frame-rates, which should give you a great deal of future-proofing even as DirectX 12 games hit the scene in the coming months. AMD's upcoming dual-GPU graphics card based on the "Fiji" silicon will most likely feature a pair of chips with similar power-tuning to the R9 Nano, so these numbers may give you a sneak peek at what to expect from that card.

The R9 Nano CrossFire duo offers over 90% performance-upscaling at 4K Ultra HD in games such as DragonAge: Inquisition and Battlefield 4 (both Frostbite-powered titles). Grand Theft Auto V, The Witcher 3, etc., also see near-perfect scaling of frame-rates at 4K. In CryEngine-powered titles like Crysis 3 and RYSE, the scaling is still an acceptable 80+ percent. The scaling is at acceptable levels, though not as high at 1440p resolution. This is because the R9 Nano CrossFire is overkill for the resolution and gets GPU frontend architecture or CPU limited. Don't even think about using the R9 Nano CrossFire at lower resolutions (1080p and below) because the scaling only gets worse.

Far Cry 4 is an interesting test. The R9 Nano CrossFire not only doesn't scale at 4K, but sees performance drop. In the same test, the dual-GPU R9 295X2 scales just fine, which goes to show that AMD still needs to refine drivers for the "Fiji" GPU. There are other tests where there is no scaling (not even for the R9 295X2), which serves to show the pitfalls for multi-GPU setups. You're at the mercy of game-developers to not completely suck at optimizing their games (*cough* Project CARS *cough*), and at the GPU vendors' to ship out multi-GPU profiles for important games in a timely manner. There's no right answer on who's at fault when a particular game doesn't play well on particular hardware. Good relations between game developers and GPU vendors make all the difference. We're in this together on the PC platform.

Just for kicks, we paired the R9 Nano with its identically-priced albeit faster and bulkier sibling, the R9 Fury X. The performance difference between this combo and a pair of R9 Nano cards is negligible across the board, even though a single R9 Fury X is 13 percent faster than a single R9 Nano. AMD drivers appear to run some kind of clock-speed parity between the two cards. If you have a Fury X and for whatever reason, later down the line, plan on adding a Nano, expect the duo to perform like a pair of Nanos.

Should you spend $1,300 on a pair of R9 Nanos? You see, the thing about halo products is that your buying decision is always irrational (eg: it's irrational to buy a GTX TITAN-X right now). In terms of performance, a pair of R9 Nano cards give you exactly what you want: a 60-90 % performance uplift at 4K Ultra HD, which should give you enough juice to crank up all your settings at 4K before commencing with drooling rainbows. It should appeal to small form-factor micro-ATX builders in particular, with the same premium case makers behind SFF mini-ITX cases also offering slightly bigger micro-ATX ones. However, if you're gaming at lower resolutions, such as 1440p, you're much better off with a single card. If it's 1080p you're gaming at, don't even buy a R9 Nano, but pick up an ITX version of the R9 380 or GTX 960 to spend the savings on literally anything else.