Build It: Three Radeon HD 7970s—One Monster PC

Posted 04/16/2012 at 12:44pm | by Nathan Edwards

22

Comments

Print

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

Triple Your Video Power, Triple Your Fun

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. 

Hardware Highlights

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. 

Installing the Cooler

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!