How-To Build An AMD/CrossFire Powerhouse PC

Nathan Edwards

Can we build an AMD machine—any AMD machine—that can compete with an Intel-powered rig?

In the forever war between CPU vendors, AMD and Intel have traded places many times—one leads, then the other. Since the advent of Intel’s Core i7, though, AMD hasn’t been able to touch the performance of Intel’s high end, and Sandy Bridge further increases the gap. But, well, you couldn't buy Sandy Bridge motherboards when I wrote this build-it story in February for the May print issue—something about a bad chipset—and I’d been meaning to build an AMD-powered machine for a while now—with CrossFire, even. Why? Partially because I can, but I also want to witness the performance delta firsthand.

Just for kicks, I’m also going to put some effort—and money—into making this system pretty. I’m not going to add lots of flashy lights (though I thought about it); instead, I’m focusing on the case itself and the wiring inside. The result, hopefully, will be a rig I can be proud of, inside and out.


Total for PC: $2,220

Choosing the Hardware

Advocates of AMD’s Phenom chips cite their low power consumption and high overclocking potential—oh yeah, and you can get a 3.2GHz hexa-core for 200 bucks. Indeed, the cost of the Phenom II X6 1090T that I chose, plus a fancy CrossFireX-enabled MSI 890FXA-GD70 motherboard, was only $400 total. This had the makings of an inexpensive build, until I added two Radeon HD 6870 videocards, a 7,200rpm 2TB Seagate Barracuda XT hard drive, and a $500 256GB Samsung solid-state drive. Why these parts? Thanks to a recent price drop, two 6870s in CrossFireX cost less than a single GTX 580, and they help me maintain the theme of AMD solidarity. I chose the drives with performance in mind, plain and simple.

Silverstone’s PP05 short-cabling kit works with any of its modular PSUs to avoid clutter in smaller cases.

Since a clean-looking, aesthetically pleasing build was also part of the plan, I sprang for NZXT’s white Phantom chassis, which looks gorgeous on the outside, has plenty of fan mounts, and is roomy enough that, even when loaded with two videocards, my build won’t look cramped. To make it look even cleaner, I’m modifying my Silverstone Strider Gold 750W PSU with Silverstone’s short-cabling kit and some of NZXT’s fancy, individually threaded power-cable extenders. Throw in a Blu-ray drive, 4GB of RAM, a copy of Windows 7, and Cooler Master’s famed Hyper 212+ CPU cooler (yes, it works on AM3!) and we’re in business.

1. Install CPU, Cooler, and RAM

AMD CPUs, unlike their Intel counterparts, still have pins on them, so be careful not to bend them when you place the CPU carefully into its socket. Make sure to align the triangle on the upper left corner of the socket with its counterpart on the CPU, then lower the lever that secures the CPU.

Next, remove the motherboard’s built-in cooler retention mechanism by unscrewing the four silver Phillips-head screws, and then remove the black plastic structure and its backplate. Most AMD coolers don’t require this, but our Hyper does. Align the Hyper 212+ backplate with the four mounting holes, then put the mounting pins through the holes and secure with the hex nuts using the hex bit included with the cooler (below). Apply a small amount of thermal paste to the CPU, then follow the Hyper’s instruction manual to secure the heatsink to the mounting pins. Tighten the spring screws until they’re no longer easy to tighten.

At this point you should add the RAM to the two slots closest to the heatsink, then clip the heatsink fan to the RAM side of the heatsink (so it blows through the cooling fins toward the back of the mobo) and plug it into the CPU_FAN header.

2. Prep the Case

Remove both side panels from the case, as well as the top and front fascia. Set them aside for now. The NZXT Phantom comes with a rat-ton of hard drive trays. In fact, there’s a whole extra bay taking up room at the bottom of the case where we could be fiddling with PSU cables. Let’s remove it. Flip the case onto its front so the bottom of the case is visible. Unscrew the four Phillips-head screws at the center of the case’s base (below), then flip the case so the rear of the motherboard tray is visible and remove the six screws you see in the center. Then you can remove that whole hard drive bay.

You should also install the motherboard I/O shield at this point. Be sure to install it from the inside of the case, facing out, and make sure all nine ATX mounting holes in the case have standoffs in them.

3. Install Mobo and GPUs

With your case lying on its left side, place the motherboard into it. Align the I/O ports with the holes in the I/O shield and the mounting holes with the case’s standoffs (above). Install using screws from the Phantom’s screws pouch. Now might be a good time to connect the front-panel HD_Audio, USB, and power connectors.

Remove the first two PCI-E slot covers, as well as the fourth and fifth. Align the first GPU with the first PCI-E x16 slot and lower it into place, pressing down firmly so it engages with the slot (above). Secure it with two thumbscrews. Because of the enormous coolers on Asus’s EAH6870 DirectCU videocards, we can’t use the second PCI-E x16 slot. Instead, we’ll put the second GPU in the third PCI-E slot, using expansion-ports 4 and 5 (below). Once both GPUs are secure, attach the CrossFire connector.

4. Install Fancy Power Cables

Before we add the PSU, we’re going to prewire our individually threaded power cables so they run behind the motherboard tray. If you’re skipping the individually threaded cables and PP05 kit, skip this step. Attach the 24-pin ATX connector to its socket (above), then push the other end through the nearest rubber-grommeted hole in the mobo tray. Attach the 8-pin ATX aux power cable to its socket, then run it up into the hole at the top of the motherboard tray and behind the mobo. Same for the four 6-pin cables for the videocards (below); attach them all first and then route them behind the motherboard.

5. Mount the Drives

Now it’s time to install the drives. Just slap the optical drive into whichever bay you’d like (we used the bottom-most optical bay) and secure it by clicking the slider on the lock mechanism to the front (above).

The Phantom’s hard drive trays are like nearly every other case’s trays—the 3.5-inch drive pops right into its bay, while the 2.5-inch drive needs to be secured with screws (above). Slide the drive trays back into the bay. Connect with the fancy 4-pin-to-3-SATA connector from the NZXT kit; garnish with SATA cables (below).

6. Install PSU and Connect Cables

Because wiring’s such a big part of this build, we’ve saved the PSU for the end. By now, everything should be installed except the PSU, and the motherboard and GPUs should be connected to individually threaded power-cable extenders that are routed behind the motherboard tray.

The Strider Gold 750W PSU comes with standard-length modular cables preinstalled; remove those. Install the PSU into the chassis and plug in the short cables from the PPO5 kit (below). You should only need the two ATX power connectors, four 6-pin PCI-E cables, one SATA power connector, and one two-plug Molex power connector.

Run the two ATX power connectors and four PCI-E power connectors through the giant hole at the bottom of the mobo tray and bring them up to connect to the individually sleeved cables (below). Utilize zip ties and the cable tie-downs available to you.

Almost done! Be sure to connect 4-pin power connectors to your front-panel fan connectors and 4-pin-to-3-SATA hard drive connectors, and be sure to connect front-panel, SSD, HDD, and Blu-ray SATA cables to the motherboard. Double-check that all your power connectors are in place, as well as your front-panel connectors. Replace the case’s right side panel and top and front plastic molding, being sure to remove the optical bezel for the slot the Blu-ray player occupies. Connect your two side-panel fans to their connectors and replace the left side panel. Connect your monitor, keyboard, mouse, and power cable, and you should be ready to install Windows. Glorious.

Our AMD Machine Is a Looker

Cooler Master Hyper 212+

It remains our go-to entry-level cooler, and it’s compatible with both AMD and Intel builds.

Fancy Wrapping

Individually sleeved cables eliminate visual clutter from the inside of the case.

Crossfire GPUs

It’s usually better to have one high-end GPU than multiple midrange cards, but dual Radeon HD 6870s are powerfully tempting.

Samsung 470 SSD

A 256GB SSD might have been overkill. But we’ve been good lately.

The AMD Rig in Action

At stock speeds, my AMD-powered rig doesn’t do so well compared to Maximum PC’s standard zero-point machine. This isn’t surprising; the Intel machine has a faster clock speed and more virtual cores (thanks to HyperThreading) than my rig. That gives it the edge in both single-threaded and multithreaded apps. That ain’t fair.

But I didn’t build this rig to run at stock speeds. After a few false starts, I got the 3.2GHz 1090T CPU running at a stable 3.8GHz. This was my second attempt at overclocking this rig; the first resulted in a bad smell and a fried motherboard somewhere around the 4GHz mark. I replaced the motherboard and got a stable 3.8GHz overclock.

The extra clocks really helped narrow the gap between this rig and our zero-point: At 3.8GHz, the AMD machine ran Lightroom 12 percent faster than the zero-point, came within 10fps of the zero-point in Far Cry 2, and exceeded it in STALKER. Thanks to multithreading, the zero-point still won in Vegas and ProShow Producer, but the gap was much narrower after our overclock.

The 1090T in my rig overclocked impressively (and has potential to go even further), but for multithreaded applications, a quad-core with HyperThreading seems to beat out a higher-clocked six-core without.

Alternate Configurations

There are several points at which your build can differ from mine. Skip the individually sleeved power cables and the Silverstone PP05 short-cable kit, and you can save almost $80. Dropping the SSD size from 256GB to 64GB puts space at a premium but saves another $370. Swapping the 4GB of DDR3/1600 for 8GB of DDR3/1300 costs only $20 more. And so forth.

The goal of this build was to experiment—both with an AMD configuration (which we haven’t done in a long time) and with CrossFire, which we also haven’t done for a while. With the overclock I achieved, the AMD rig performed soundly.

The secondary goal was to build a beautiful rig, and in that sense I definitely succeeded. Just look at that gut shot.


Zero Point
Build-it 3.2GHz
Vegas Pro 9 (sec)
4,982 (-39%)
Lightroom 2.6 (sec)
355 (-0%)
ProShow 4 (sec)
1,674 (-34%)
Reference 1.6 (sec)
2,113 2,615 (-19%)
STALKER: CoP (fps)
42 42.8
Far Cry 2 (fps)
114.4 98.8 (-14%)

Our current desktop test bed consists of a quad-core 2.66GHz Core i7-920 overclocked to 3.5GHz, 6GB of Corsair DDR3/1333 overclocked to 1750MHz, on a Gigabyte X58 motherboard. We are running an ATI Radeon HD 5970 graphics card, a 160GB Intel X25-M SSD, and 64-bit Windows 7 Ultimate.

Zero Point
Build-it 3.8GHz
Vegas Pro 9 (sec)
4,246 (-28%)
Lightroom 2.6 (sec)
ProShow 4 (sec)
1,493 (-26%)
Reference 1.6 (sec)
2,113 2,229 (-5%)
STALKER: CoP (fps)
42 42.9
Far Cry 2 (fps)
114.4 105 (-8%)

Our current desktop test bed consists of a quad-core 2.66GHz Core i7-920 overclocked to 3.5GHz, 6GB of Corsair DDR3/1333 overclocked to 1750MHz, on a Gigabyte X58 motherboard. We are running an ATI Radeon HD 5970 graphics card, a 160GB Intel X25-M SSD, and 64-bit Windows 7 Ultimate.

Around the web