X79. CrossFireX. XMP. This month I’m going to build a gaming rig that tears our benchmarks a new one. Or several new ones
Editor's Note, 4/16/12: When I built this rig for the April 2012 print edition, the Nvidia GTX 680 had not been released. Also, all prices listed were accurate as of the time this rig was built; many have now dropped.
My first X79 build, back in November 2011, was pretty modest. Well, as modest as a PC with a 1,000-dollar processor can be. It performed well in CPU-intensive benchmarks, but it had only a single GTX 580, so it did about a third as well as top-tier systems in graphics tests.
Back when I built that PC, the Core i7-3960X was the only Sandy Bridge-E CPU available to us, and the GTX 580 was the fastest single-GPU card on the market. Well, this time I’m going to build a Sandy Bridge-E system with the new quad-core Core i7-3820 and the new fastest single-GPU videocard on the market: AMD’s Radeon HD 7970.
Wait, just kidding. I’m not going to use a 7970. I’m going to use three of ‘em!
Update: Fixed hard drive name and capacity
Since I know I want to use three Radeon HD 7970s in CrossFireX configuration, I’ll need an X79 motherboard that supports CrossFireX. Gigabyte’s X79-UD5 has three x16 PCIe 3.0 slots, as well as a nifty backup BIOS that (spoiler alert) totally saves my butt later. It also supports the DDR3/2133 XMP profile of my G.Skill Ripjaws Z RAM.
The Core i7-3820 isn’t an unlocked part, but I can still get an easy Turbo Boost overclock to 4GHz with it, and it has to share a chassis with three Radeon HD 7970s, which put out a lot of heat. So I’m using Noctua’s NH-D14 SE2011, an exceptional air cooler.
All these beefy components need room, air, and power. For the first two needs I’m going with NZXT’s Switch 810 chassis. It’s big, roomy, good-looking, and has plenty of fan support. I especially like the pivoting drive-bay fan mounts that can aim cool air directly at the videocards, and I’m going to add a fan to the lower one.
I’m also going to need a powerful PSU with enough juice for my rig; Silverstone’s Strider Gold 1200W is fully modular and can support all three GPUs and my slightly overclocked proc, too.
A speedy 256GB Samsung 830 Series SSD makes for a good Windows drive, and a 3TB Seagate Barracuda will sit in the Switch 810’s hot-swap bay.
Aside from a few steps, this is a pretty standard build, so I’ll skip the complete step-by-step and just call out a few interesting steps on the way. For the most part, you’ll be fine following the case and motherboard instructions.
Thanks to the integrated backplate on the LGA2011 socket, it’s not necessary to preinstall the CPU cooler before you install the motherboard. I put the CPU and RAM in my board and installed it in my case before I put in the cooler. One word of caution: If you’re not using the RAM I used, make sure the heat spreaders aren’t too tall; the Noctua NH-D14 cooler overhangs some of the RAM slots and can conflict with oversized RAM heat spreaders.
To install the NH-D14, first mount the four double-ended thumbscrews into the screws on the socket, then install the crossbeams and secure them with the included nuts.
Once the mounting bracket is in place, apply a dot of thermal paste the size of a small pea to the center of the CPU. Remove the cooler’s center fan and place the cooler on the heatsink such that the spring screws line up with the posts on the crossbar. Tighten the spring screws, alternating screws each few rotations until the screws stop turning. Reattach the fan, making sure it’s pointing the same direction as the front fan, plug both fans into the Y-cable, and plug it into the CPU_FAN header.
Next up: Installing the fans and video cards!
The Switch 810 has a decent array of stock fans, but I have three GPUs super-heating the air and I want to make sure they’re adequately ventilated. I really like the pivoting fan mounts on the backs of the two hard drive cages, but only the top one has a fan preinstalled, so I’m going to add one to the bottom cage, as well.
Remove the thumbscrews at the top and bottom of the drive cage and pull it out of the chassis. Use fan screws to install the fan into the mount—only the top two mounting holes will be used.
Adjust the fan so that it’s pointing up where the GPUs will be and reinstall the cage into the case. Run the fan cable behind the motherboard tray and plug it into the fan controller there.
Because they take up so much room in the case, I installed the GPUs last—after I installed the DVD burner, hard drive, and SSD, after I mounted the PSU and connected all the power cables, even after I connected the case’s front panel connectors.
Install the topmost GPU into the topmost x16 PCIe slot, then the other two in order. You should have three PCIe power cables from the PSU, with an 8-pin and a 6-pin power connector on each. Connect one cable per videocard, making sure to power both the 8- and 6-pin connectors on each card.
Use one CrossFire bridge to connect the first and second videocards, and another to connect the second and third, as shown.
Next up: Benchmarks and conclusion!
Once the machine was built and the wiring tidied up a bit, I fired it up and installed Windows and all the drivers, then I updated the BIOS to the latest version and did a bit of overclocking. Well, my first attempt at updating the BIOS corrupted it. Fortunately the Gigabyte board automatically restored the BIOS from its backup, and I was able to successfully update that. A simple multiplier overclock brought the proc to 4GHz—not very ambitious, but very safe. I also made sure my RAM was set to its XMP profile timing of DDR3/2133. These efforts gave me modest improvements over the stock-clocked state in the CPU- and memory-bound benchmarks.
So how does my CrossFireX rig stack up? Against our aged zero-point it’s a slaughter: anywhere from 15 to 32 percent faster in CPU-bound benchmarks, and a whopping 238 percent improvement in STALKER: Call of Pripyat and 92 percent in Far Cry 2. So to make things interesting, I also tested it against our 2011 Dream Machine.
In CPU tests, the Dream Machine clearly has the edge—namely, a 20 percent clock advantage. With its unlocked 2600K overclocked to 4.8GHz, it crushed the i7-3820 in this month’s rig, which was a whopping 23 percent slower than its older rival in MainConcept Reference and 12 percent slower in Vegas Pro 9.
In graphics-bound tests, though, the Dream Machine is dethroned. The triple Radeon HD 7970s proved their mettle against even Superclocked GTX 580s, with 13 percent gains in Stalker and 24 percent in Far Cry 2. The triple 7970s are so powerful, actually, that they edge out the dual overclocked GTX 590s found in the CyberPower Fang III reviewed in this issue (page 76). That’s triple CrossFireX beating quad SLI!
As if that weren’t impressive enough, this rig puts out the second-highest 3DMark 11 Extreme score of any machine we’ve tested, at X7,619. That’s just a tiny bit below the X7,785 set by the Maingear rig we tested in February 2012. And Unigine Heaven 2.5? Try 75.4fps with all settings maxed out. That’s 5fps more than the dual Asus Mars II cards (quad GTX 580s) in the Maingear. For reference, the mighty Dream Machine’s three 580 cards came in at X5,863 in 3DMark and 43.4 fps in Heaven.
True, the rig I’ve built lacks water-cooling, a Blu-ray drive, or scads of storage. It’s also got a CPU with a modest overclock. But thanks to the extraordinary performance of its three Radeon HD 7970s, it’s a hell of a lot of rig for under $3,400.