Last year, AMD made waves in the high-end GPU market with a new high-end variant of its GCN architecture. If you'd asked me back then whether the company would ever release a dual GPU version of the Hawaii graphics card, I'd have said no. The Radeon R9 290 and R9 290X were impressive performers, but these cards ran hot -- so much so that AMD had to tweak its TDPs and available cooling solutions in an attempt to balance the GPU's high-end performance and ruinous thermal output.
The solution to that problem, it turns out, was vastly better GPU cooling. The R9 295X2 has an Asetek-built liquid cooling system with two separate heatsinks and radiator pumps and a fan in the center to drive cold air over both heatsinks at the same time. This type of cooler has been popular for high-end CPUs for several years and we've seen a few GPU models before, but never anything quite like this.
Why two independent heatsinks backed by liquid reservoirs? Because the R9 295X2 packs an awe-inspiring 500W TDP. As near as I can tell, that's the highest power consumption we've ever seen on a GPU; it puts the HD 7990 and GTX 690 to shame (both cards had an approximate TDP of 375W). The reason for this is straightforward -- the R9 295X2 is two full implementations of the Hawaii GPU on a single PCB running at slightly higher clocks with the same 4GB of RAM per GPU.
Multi-GPU scaling, product positioning
AMD's last multi-GPU graphics card, the HD 7990, was dogged by the immaturity of its own frame pacing solution, but there's reason to hope that situation will play out differently this time around. The dual-GPU configuration on this card still communicates via XDMA and they'll use the same 48-lane PCI-express bridge chip from PLX to do it. That core, the PEX8747, is a 48-lane PCIe solution that dedicates 16 lanes to each GPU and 16 lanes to the CPU.
This XDMA solution should drastically improve AMD's frame latencies vis-a-vis Nvidia -- our tests with asymmetric Crossfire last fall showed significant promise -- and it means that would-be buyers may be guaranteed a better multi-GPU solution from AMD than the company has previously been able to make available. AMD put a great deal of work into fixing its frame pacing in software over the past 12 months, but the bottom line is that a hardware solution to this problem is a better, simpler fix for customers.
Finally, there's positioning. With a price of $1500, AMD is planning to take the just-announced Titan Z out at the knees. To be fair, Nvidia's asking price for the Titan Z was ridiculous to start with -- at $3000, the GPU is 50% more expensive than a pair of Titan Blacks in SLI, which would provide equivalent performance. That price tag was either an attempt to soak funds from HPC developers with limited case space, or to appeal to buyers who care more about packing as many GPUs into as small a space as possible, rather than a reasonable price target for the card.
The bigger question is whether or not this card can compete effectively against its challengers from the bottom -- specifically the R9 290X and GTX 780 Ti or Titan Black running in multi-GPU configurations.
Next page: Temperatures and noiseTemperatures and noise
AMD's R9 290 and R9 290X both struggled to keep their operating temperatures below 95C. At low fan speeds, users sacrificed performance. At high fan speeds, they risked never being able to listen to a singer with a higher voice than Barry White. The R9 290X balanced this with fan profile settings that helped alleviate the problem, but both cards were very loud compared to Nvidia hardware.
You might not believe it from a GPU with a 500W TDP, but the R9 295X2 is a vast improvement. The tone of the noise has fundamentally changed; while the R9 295X2 is slightly louder than an R9 290X according to dB meters, the sound is much lower pitched and far more bearable. The GPU temperature, meanwhile, sits at just 67C after prolonged testing in a case-closed environment.
For a dual-GPU solution, this is just about unheard of. Most multi-GPU configurations run significantly hotter because the top card ends up doing more work and has limited access to cool air. That's simply not a problem here. Be advised, however, that AMD is not kidding around when it says this card has a 500W power draw. If your PSU can't deliver a minimum of 28A per 12V rail, you run the risk of killing it. This includes ultra-high end power supplies -- a 1200W PSU with multiple 12V rails may not be able to deliver enough amperage to actually power this card.
Performance
We put AMD's R9 290X and Nvidia's Titan Black up against the R9 295X2, but don't have a second Titan Black to compare against in SLI. In this case, the Titan Black is an effective stand-in for the GTX 780 Ti -- the two cards are clocked nearly identically, with the Titan Black offering 6GB of RAM against the 780 Ti's 3GB. Below 4K, this difference almost never matters, even modern titles typically use ~2GB of RAM or less. Even at 4K, it's not clear that we'll see much improvement -- but if there's going to be a boost, it's going to happen at that resolution. We tested all three cards on an Intel Core i7-4770K with 16GB of DDR3-2133 and a Gigabyte Z87X-D3H motherboard. The latest drivers from AMD and Nvidia, (NV's just-released 337.50 Beta) were used.
A quick check of other reviews(Opens in a new window) shows the R9 295X2 is mostly tied against the 780 Ti in SLI, just as the R9 290X ties up against the GTX Titan Black. When the R9 290X was $550 going up against a 780 Ti at $700, tying on performance was a great win for the card's overall price/performance ratio. With the R9 295X2 marching into battle as the most expensive solution on the block, that's no longer the case.
Next page: Gaming benchmarksMetro Last Light
This sequel to Metro 2033 is known for punishing graphics cards even at 1920x1080 -- how does it handle 4K? We tested the game at the same detail settings -- Very High Detail with SSAA enabled, normal tessellation, and Nvidia's Advanced PhysX disabled.
At 1080p, all three of our GPUs turn in perfectly playable results, with the Titan Black and R9 290X tying things up and the R9 295X2 offering a 50% performance boost. At 4K, it's a fundamentally different story. Of our three test chips, only the R9 295X2 can deliver a playable frame rate with SSAA enabled. Both the R9 290X and Titan Black slam into fill rate limitations -- disable smooth-screen antialiasing, and frame rates double at 4K on both of those cards.
Total War: Rome 2
We've swapped out Total War: Shogun 2 for the newer equivalent, Total War: Rome 2. Like Shogun 2, Rome 2 contains a built-in benchmark -- but it's difficult enough for modern cards to run that we eschewed our usual practice of pushing everything to maximum detail and opted instead for the "Extreme" preset.
Again, the R9 295X2's power is largely wasted at 1080p. If you push everything to maximum settings at 1080p this isn't true; the R9 295X2 scores just 36 fps in that mode at 1080p -- but that also leaves the other two GPUs at an unplayably low frame rate. In 4K, the scaling is much stronger. Nvidia's latest driver release predicts far stronger scaling in Rome 2 than the company could previously muster. If we assume AMD and NV offer roughly equal scaling percentages, then a pair of Titan Blacks in SLI should end up hitting the same point as the AMD R9 295X2.
BioShock Infinite
BioShock Infinite is an Unreal Engine 3-based game that isn't too hard on either high-end GPU; it's one of the few titles that every card can push at maximum detail, even in 4K. This follow-up to BioShock and BioShock 2 is a gorgeous exploration of the flying city of Columbia and a worthy expansion of the BioShock universe.
Up until now, the GTX Titan Black and R9 290X have been neck-and-neck in their various comparisons, this is the first time we see the Titan Black take a decisive lead at both 1080p and 4K resolutions. While the R9 295X2 wins overall, the gap between it and the Titan Black is smaller.
Company of Heroes 2
Company of Heroes 2 is a sequel to the popular Company of Heroes; the RTS title focuses on the Eastern Front of World War 2 and uses THQ's proprietary Essence 3.0 engine. COH2 is unique among the games we tested in that it doesn't support SLI or Crossfire -- we've included it here because it's important to remember that when games don't launch with Day 1 support, you're often left stuck with single-GPU performance until AMD or Nvidia updates their drivers.
All three GPUs stack up identically across both 1080p and 4K, though the Titan Black does fall behind slightly in that mode. RTS games don't require the same high frame rates as their FPS cousins, but this is too low to be considered playable without some detail drops.
Battlefield 4
Our Battlefield 4 benchmark uses the 64-person Golmud Railway map. All three cards were tested in 1920x1080 at Ultra Detail; the AMD cards were also tested using Mantle. Battlefield 4 shows rather different performance figures than our tests; here the GTX Titan Black is well ahead of the R9 290X in Direct3D. The gap narrows, but doesn't vanish altogether, when we switch to Mantle.
Mantle doesn't particularly benefit the R9 295X2 in 1080p, but 4K performance is up slightly, to 74 fps. Oddly, Mantle didn't show the same benefits here that we saw in late January in dual-GPU configurations. Back then, Mantle gave our Core i7-4770 testbed quite a kick -- here, performance regressed significantly on the R9 295X2.
Next page: ConclusionConclusion
The R9 295X2 isn't just fast. For $1500, "fast" is mandatory. AMD's engineers have slapped two of its highest-end GPUs on the same board while holding GPU temperatures below 70C. The dual-GPU card is far, far less annoying under load than a single R9 290X. That's what makes this card extraordinary. The R9 290 and R9 290X reference designs asked consumers to compromise on noise in return for top-tier performance. The R9 295X2 asks nothing of the sort -- provided you're willing to pay $1500 for the privilege.
Right now, a pair of GTX 780 Ti cards will set you back $1320, while a brace of GTX Titan Blacks like the card we tested today would be $2000. The 3GB frame buffer limit on the 780 Ti may be a limit in future 4K titles, but we haven't seen a game yet that had a problem with it. On the AMD side of the fence, a pair of R9 290Xs can be had for just $1140, but we've played with running two of these cards in Crossfire before. Even with high-end coolers, they dump an enormous amount of heat and noise into a system -- so much so that using a rig with two R9 290Xs is unpleasant while wearing headphones. There's no question that the R9 295X2 is much, much quieter than any conventional cooling solution -- but AMD is asking a $360 premium for that cooler design.
AMD has played up the R9 295X2 as a vastly superior solution compared to the Titan Z. Given that other reviews show the R9 295X2 tied against the GTX 780 Ti SLI, that's a fair point, but it mostly illustrates just how ludicrous Nvidia's proposed $3000 price tag is. But while the R9 295X2 is a much better solution at $1500 with a two-slot cooler than a $3000 hypothetical Titan-Z with a 2.5-slot design, that's not the card AMD is competing against today.
At $1300, the R9 295X2 would be a killer, best-in-class solution. At $1500, you're paying a premium for the noise level and the single-card design as opposed to the raw performance. That's not a bad thing, but it means that AMD is hanging its proverbial hat on the overall experience of owning the R9 295X2 as opposed to the killer price/performance ratio that characterized the R9 290 and R9 290X.
If you care about 4K gaming and you want an excellent balance between price, performance, and GPU temperature all on the same card, then the R9 295X2 is the best solution you can buy today. How many customers fit that bill? We'll have to wait and see.
