Build a hellacious PC with Intel's Devil's Canyon and AMD's dual-GPU graphics monster

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The inevitable march toward greater and more glorious PC performance continues unabated. Earlier this year, Intel released the Core i7-4790K, a quad-core beast that lays claim to being the company's first-ever 4GHz processor, with clock speeds that can leap to 4.4GHz when needed. Even Intel's latest fire-breathing Haswell-E "Extreme Edition" chips can’t claim that!

What’s more, Devil’s Canyon chips sport redesigned packaging materials and new high-performance thermal paste, among other power-tweaking features. In other words, this puppy is built to game like a pro and overclock like a champ.

After building yesterday’s outrageous Haswell-E system, we were left wondering: What if you wanted to spend a similar amount on a rig revolving purely around PC gaming, with no need for Haswell-E’s eight hyperthreaded cores? Ditching that $1,000 processor and swapping in the $340 (and higher-clocked) Core i7-4790K leaves you with a lot of extra money to spend on visual firepower.

While our Haswell-E build featured the Nvidia GTX 980, the most powerful single-GPU graphics card available today, the savings incurred by using Devil’s Canyon allowed us to upgrade to even more potent graphics hardware: AMD’s R9 R95X2, a ludicrously potent video card powered by not one, but two discrete high-end graphics processors.

This ought to be fun. Buckle up and get ready to bask in our latest loving example of the type of glorious gaming excess only possible on PCs.

Component selection

intel devil canyon cpu Marco Chiappetta

Intel's Devil's Canyon processor.

Since we already had the 4GHz Core i7-4790K processor pegged for this build, choosing a motherboard was easy. We knew we wanted a board based on Intel’s latest Z97X chipset that cut zero corners whatsoever. Gigabyte’s Z97X-Gaming G1 WiFi-BK seemed to fit the bill perfectly.

This motherboard is pricier than most other Z97X-based products, but Gigabyte goes the extra mile by packing the Z97X-Gaming G1 WiFi-BK with a Killer NIC, Creative Labs audio, a host of overclocking-related features, and the highest-quality caps and chokes. The company even includes a ton of accessories, like braided SATA cables and a wireless adapter. Gigabyte also goes so far as to burn in these motherboards with an overclocked CPU to ensure reliability and stability. Boards that don’t pass muster never make it out to retail. Few Z97X-based motherboard are as hardcore as the Z97X-Gaming G1 WiFi-BK.

AMD radeon 295x2 Marco Chiappetta

AMD's R9 295X2 dual-GPU graphics card, complete with integrated closed-loop water cooler.

To allow the Core i7-4790K to stretch its legs when playing games, we paired the processor to AMD’s afoementioned ultra-powerful Radeon R9 295X2. The Radeon R9 295X2 features a pair of AMD Hawaii-class GPUs, 8GB of memory, and a custom, closed-loop water-cooling system that allows the GPUs to be clocked as high as 1,108MHz. (Fans alone won’t cut it with this beast!) The end result is a single graphics card that’s more powerful than a pair of Radeon R9 290X cards running in CrossFire. The sticker price is just as astronomical as this card’s performance, but the Radeon R9 295X2 is an excellent dance partner for Devil’s Canyon.

Continuing with the high-end theme of this build, we outfitted the rig with 16GB of RAM. The choice of kit may seem weird—we went with a 16GB (8GB x 2) DDR3-1866 AMD Radeon Performance Series kit. Why an AMD-branded memory kit? It was available at a competitive price and offered a high-capacity, paired with relatively low-latency and voltage. It, uh, also happened to match the color-scheme of the Gigabyte motherboard. These AMD-branded memory kits are produced by Patriot anyway, and work perfectly fine in an Intel-based system. Heck, the kit even has an XMP profile available for quick-and-easy configuration.

AMD build storage Marco Chiappetta

The Samsung 850 Pro SSD and Lite-On optical drive we used for this build.

To handle our storage needs, we snatched up one of the most impressive solid state drives we’ve seen to date, a 1TB Samsung SSD 850 PRO. Many of today’s fastest solid state drives flirt with the upper limits of the SATA interface in terms of peak, sequential transfer speeds, so little differentiates the drives in that regard. The Samsung SSD 850 PRO, however, is measurably faster than most other drives with small, random transfers, which can noticeably enhance the user experience during day-to-day computing tasks. Factor in the drive’s high capacity and 10-year warranty, and it was a perfect fit.

We also threw a cheap, Lite-On DVD-R optical drive into the system in the unlikely event we’d need to use physical media at some point.

The Core i7-4790K isn’t a particularly power-hungry CPU, but the Radeon R9 295X2 needs a ton of juice to operate reliably. In fact, AMD exceeded the standard specifications for the dual supplemental PCIe 8-pin feeds on the card. Typically, a PCI Express 8-pin feed can offer up to 150 watts, and the PCI Express graphics slot can feed another 75W. Add that all up and the Radeon R9 295X2’s dual-8-pin feeds and slot shouldn’t require more than 375W—but the card actually has a 500W TDP (thermal design point).

corsair rm1000 power supply

As such, the Radeon R9 295X2 needs a PSU capable of pumping out 28 amps on each of the 12-volt rails connected to the card, or a powerful single rail. With that in mind, we went with a Corsair RM1000 1000-watt modular unit, which features a single-rail design capable of 83.3A on its 12V rail. The RM1000 is also quiet and 80 Plus Gold certified.

Further reading: How to pick the best PC power supply

To house all of our components, we chose a Rosewill Blackhawk mid-tower, which features mesh top and front panels and an array of included cooling fans. The Blackhawk offers excellent cooling performance for the money. Also, its specs claimed it could support graphics cards up to 16 inches, thanks to some removable drive cages—though as you’ll see in a bit, we ran into some snags. (Thankfully, they weren’t insurmountable.)

And speaking of cooling performance, the last piece of kit we should mention is the Thermaltake NiC 4 cooler. The Core i7-4790K has a max TDP of only 88W, but we wanted a CPU cooler that afforded a bit of headroom for overclocking. The Thermaltake NiC 4 is capable of dissipating up to 180W with its dual 120mm fans and over-sized, tower-type heatsink. It's also affordable and relatively quiet.

If you’re keeping track, the complete parts breakdown for the system is as follows:

  • CPU: Intel Core i7-4790K - $340
  • Motherboard: Gigabyte Z97X-Gaming G1 WiFi-BK - $350
  • Memory: AMD Radeon Performance Series 16GB DDR-1866 - $160
  • GP : AMD Radeon R9 295X2 - $1000
  • Storage: Samsung SSD 850 PRO 1TB - $660
  • Optical drive: Lite-On DVD-R - $20
  • Chassis: Rosewill Blackhawk - $80
  • Power supply: Corsair RM1000 1000W PSU - $180
  • CPU cooler: Thermaltake NiC 4 - $45
  • Operating system: Windows 8.1 OEM - $100

The complete system costs $2,935.

You could deduct the OEM copy of Windows 8.1 to save a little cash. At just under $3,000, this system is pricey by almost anyone’s measure (though still around $500 cheaper than our Haswell-E build). However, it also represents one of the most powerful, bleeding-edge PCs you could build today.

Turning the screws

Assembling most systems is relatively easy. The CPU, GPU, and RAM are keyed and fit into their respective sockets or slots only one way, and it’s easy to tell which slots fit which add-in boards as well.

foundation AMD build Marco Chiappetta

The assembled motherboard, with RAM, CPU, and CPU cooler installed.

Occasionally, however, you’ll run into a snag or two with things like over-sized coolers that interfere with RAM slots, or a drive bay that blocks the installation of an extra-long graphics card. The latter affected us this time around.

Though the Rosewill Blackhawk can accommodate graphics cards up to 16 inches long, it appears that’s only when used with motherboards that don’t put the first PEG slot in the top-most position. Even with the top drive cage removed, the Radeon R9 295X2 bumped up against a mounting bracket in the case. We were, however, able to pry the mount upward with a pair of pliers, since the mount was for the drive cage we wouldn’t be using anyway.

We also had to contend with a second graphics-card-related issue. The Radeon R9 295X2 has a closed-loop liquid cooling setup that requires mounting its radiator in a 120mm fan location somewhere on the case. We planned to put the radiator on the rear 120mm fan location on the Rosewill Blackhawk, but it proved impossible to line up the mounting holes perfectly.

AMD build done Marco Chiappetta

It took some creative assembling to fit our build inside the Rosewill Blackhawk case.

After relocating the Blackhawk’s stock fan to the top of the case where there was a second available mounting location—and where the Radeon’s radiator also wouldn’t fit, thanks to our oversized CPU cooler—we attempted to squeeze in the radiator, but it still bumped up against a ridge just above the motherboard’s rear I/O panel. Ultimately, we simply used two of the holes in the case’s fan grille to mount the radiator, rather than the pre-drilled screw holes, which worked well enough. We would have preferred to use all four screws to hold the radiator in place, but it was secure enough with two screws, so we lived with it.

Routing the Radeon's liquid-cooling tubing around the CPU cooler posed another challenge. If the tubing had butted up against sharp metal in the CPU cooler, we would have had to find another solution. The tubing barely touched the edge of a plastic fan and didn’t hinder the blades, so we wrapped the tubing around the front of the CPU cooler and let it ride.

Mounting and installing all of the other components posed no problems, thankfully.

If you’d like more detailed steps on assembling a PC, familiarize yourself with PCWorld’s guide to PC building best practices. Our instructions on how to properly install a CPU cooler will help ensure you get that critical installation right the first time, every time.

The end result

This system was worth the bruised knuckles and stress. It's a beast even without tapping into Devil's Canyon's overclocking potential.

pcw devils primary

We used a handful of readily-available benchmarks to quantify the performance of our Devil’s Canyon-based rig, including 3Dmark, Unigine Heaven, Cinebench, and PCMark. If you’d like to compare the performance of your system against ours, go for it, but be warned—you’ll probably feel a little inadequate afterward.

In the 3DMark Fire Strike Extreme benchmark, our system put up a very strong score of 8,626, which was higher than 90-plus percent of the systems in Futuremark’s database. In the Unigine Heaven benchmark (v4.0), with Ultra quality settings at a resolution of 2560x1600 with 4X anti-aliasing and maximum tessellation enabled, the system scored 1,511 (with an average frame rate of 60 FPS)—another strong showing. In the popular Cinebench R15 benchmark, the system put up 153.58 frames per second in the OpenGL test and scored and excellent 885 points in the multi-threaded CPU test. In terms of overall system performance, our Devil’s Canyon build scored 6,847 PCMarks with the latest build of PCMark 7, and its storage score was an impressive 5,621.

Over and above the benchmarks scores, the system is simply as fast, smooth, and responsive as we've seen to date. The relatively high core clocks on the CPU, copious amount of memory, speedy SSD, and ultra-powerful graphics card culminate in what is essentially a no-compromise system.

It is, however, a total Jekyll and Hyde with regard to power consumption. After idling for a few minutes, with the screen dimmed, the system pulls only 87 watts from the outlet. When sitting idle at the Windows desktop with the screen lit up, power consumption is not much different and hovers right around the 94-watt mark. Fire up a CPU-intensive task, however, and power consumption jumps up into the 210 watt range. Throw something at the system that loads both the CPU and GPU—like 3DMark—and power consumption shoots up to roughly 635 watts. By comparison, our Haswell-E and GTX 980 build from yesterday sips a mere 256 watts under full gaming loads.

The Devil’s Canyon-based Core i7-4790K may be significantly more power-hungry than its lower-clocked siblings, but the Radeon R9 295X2 is simply a monster in every possible way. Stay tuned tomorrow for a PC built entirely with AMD technology!

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