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AMD's Radeon R9 295 X2 graphics card reviewed


Hawaii is surrounded by water, right?
— 7:00 AM on April 8, 2014

Several weeks ago, I received a slightly terrifying clandestine communique consisting only of a picture of myself in duplicate and the words, "Wouldn't you agree that two is better than one?" I assume the question wasn't truly focused on unflattering photographs or, say, tumors. In fact, I had an inkling that it probably was about GPUs, as I noted in a bemused news item.

A week or so after that, another package arrived at my door. Inside were two small cans of Pringles, the chips reduced to powder form in shipping, and a bottle of "Hawaiian volcanic water." Also included were instructions for a clandestine meeting. Given what had happened to the chips, I feared someone was sending me a rather forceful signal. I figured I'd better comply with the sender's demands.

So, some days later, I stood at a curbside in San Jose, California, awaiting the arrival of my contacts—or would-be captors or whatever. Promptly at the designated time, a sleek, black limo pulled up in front of me, and several "agents" in dark clothes and mirrored sunglasses spilled out of the door. I was handed a document to sign that frankly could have said anything, and I compliantly scribbled my signature on the dotted line. I was then whisked around town in the limo while getting a quick-but-thorough briefing on secrets meant for my eyes only—secrets of a graphical nature, I might add, if I weren't bound to absolute secrecy.

Early the next week, back at home, a metal briefcase was dropped on my doorstep, as the agents had promised. It looked like so:


After entering the super-secret combination code of 0-0-0 on each latch, I was able to pop the lid open and reveal the contents.


Wot's this? Maybe one of the worst-kept secrets anywhere, but then I'm fairly certain the game played out precisely as the agents in black wanted. Something about dark colors and mirrored sunglasses imparts unusual competence, it seems.

Pictured in the case above is a video card code-named Vesuvius, the most capable bit of graphics hardware in the history of the world. Not to put too fine a point on it. Alongside it, on the lower right, is the radiator portion of Project Hydra, a custom liquid-cooling system designed to make sure Vesuvius doesn't turn into magma.

Mount Radeon: The R9 295 X2
Liberate it from the foam, and you can see Vesuvius—now known as the Radeon R9 295 X2—in all of its glory.

You may have been wondering how AMD was going to take a GPU infamous for heat issues with only one chip on a card and create a viable dual-GPU solution. Have a glance at that external 120-mm fan and radiator, and you'll wonder no more.


If only Pompeii had been working with Asetek. Source: AMD.

The 295 X2 sports a custom cooling system created by Asetek for AMD. This system is pre-filled with liquid, operates in a closed loop, and is meant to be maintenance-free. As you can probably tell from the image above, the cooler pumps liquid across the surface of both GPUs and into the external radiator. The fan on the radiator then pushes the heat out of the case. That central red fan, meanwhile, cools the VRMs and DRAM on the card.

We've seen high-end video cards with water cooling in the past, but nothing official from AMD or Nvidia—until now. Obviously, having a big radiator appendage attached to a video card will complicate the build process somewhat. The 295 X2 will only fit into certain enclosures. Still, it's hard to object too strongly to the inclusion of a quiet, capable cooling system like this one. We've seen way too many high-end video cards that hiss like a Dyson.

There's also the matter of what this class of cooling enables. The R9 295 X2 has two Hawaii GPUs onboard, fully enabled and clocked at 1018MHz, slightly better than the 1GHz peak clock of the Radeon R9 290X. Each GPU has its own 4GB bank of GDDR5 memory hanging off of a 512-bit interface. Between the two GPUs is a PCIe 3.0 switch chip from PLX, interlinking the Radeons and connecting them to the rest of the system. Sprouting forth from the expansion slot cover are four mini-DisplayPort outputs and a single DL-DVI connector, ready to drive five displays simultaneously, if you so desire.

So the 295 X2 is roughly the equivalent of two Radeon R9 290X cards crammed into one dual-slot card (plus an external radiator). That makes it the most capable single-card graphics solution that's ever come through Damage Labs, as indicated by the bigness of the numbers attached to it in the table below.

Peak pixel
fill rate
(Gpixels/s)
Peak
bilinear
filtering
int8/fp16
(Gtexels/s)
Peak
shader
arithmetic
rate
(tflops)
Peak
rasterization
rate
(Gtris/s)
Memory
bandwidth
(GB/s)
Radeon HD 7970 30 118/59 3.8 1.9 264
Radeon HD 7990 64 256/128 8.2 4.0 576
Radeon R9 280X 32 128/64 4.1 2.0 288
Radeon R9 290 61 152/86 4.8 3.8 320
Radeon R9 290X 64 176/88 5.6 4.0 320
Radeon R9 295 X2 130 352/176 11.3 8.1 640
GeForce GTX 690 65 261/261 6.5 8.2 385
GeForce GTX 770 35 139/139 3.3 4.3 224
GeForce GTX 780 43 173/173 4.2 3.6 or 4.5 288
GeForce GTX Titan 42 196/196 4.7 4.4 288
GeForce GTX 780 Ti 45 223/223 5.3 4.6 336

Those are some large values. In fact, the only way you could match the bigness of those numbers would be to pair up a couple of Nvidia's fastest cards, like the GeForce GTX 780 Ti. No current single GPU comes close.

There is a cost for achieving those large numbers, though. The 295 X2's peak power rating is a jaw-dropping 500W. That's quite a bit higher than some of our previous champs, such as the GeForce GTX 690 at 300W and the Radeon HD 7990 at 375W. Making this thing work without a new approach to cooling wasn't gonna be practical.