Quiet SLI Gaming PC Build Guide

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Quiet SLI Gaming PC Build Guide

March 5, 2015 by Lawrence Lee

Since we began posting gaming build guides last fall, we've only used single video card configurations, and for good reason. For most gamers one high-end GPU has enough horsepower to render even the most demanding games smoothly at the most common native monitor resolutions of 1920x1080 and 1920x1200. However, there is a vocal subset of enthusiasts who demand more, in particular those with QHD/4K monitors or multiple displays with up to four times as many pixels.

To game at higher than HD resolutions, two or more cards in CrossFire or SLI is practically a necessity. In the past, it was a forgone conclusion that even a dual GPU system would be hopelessly loud without an elaborate cooling solution. While heavy duty aftermarket heatsinks are available and liquid GPU cooling is starting to become more popular, neither with current GPU technology. The GeForce GTX 900 series has substantially lower power consumption than Nvidia's previous generation of GPUs as well as AMD's Radeon counterparts, making it much easier to cool with stock cooling solutions.

This article, the 8th in our Quiet Gaming PC Build Guide series, details the component selection, assembly and fine tuning process of creating a very quiet gaming system based around two GTX 970 graphics cards.


GPU: Zotac GeForce GTX 970 AMP! Extreme Core Edition x 2 - US$380 each


  • Asus Strix GTX 980 - US$565
  • MSI GTX 980 Gaming - US$560
  • Asus Strix GTX 970 - US$330
  • MSI GTX 970 4GD5T OC - US$330

Generally there are two types of SLI/CrossFire systems, the √ľber rig that uses the fastest GPUs available, and the more value-oriented machine with slower cards that combine to match/outperform single higher model cards. Our build is the later, utilizing a pair of GeForce GTX 970's from Zotac. The GTX 980 is the single GPU king but it holds only a 10~15% performance advantage over the 970, while carrying a more than 60% cost premium. Benchmarks conducted by various tech sites place a pair of 970s well ahead of a single 980 and not far behind dual 980s.

However, the GTX 970's contentious memory allocation issue can't go unmentioned. Without getting into the nitty-gritty details, the way the new Maxwell architecture works negatively affects the GTX 970's memory subsystem. While each and every 970 physically has 4GB of onboard memory, the last 0.5GB can only be accessed at a very low speed compared to the first 3.5GB. When 3.5GB of memory usage is exceeded, some games can stutter or even freeze up.

This is not an insignificant problem as high memory usage goes hand-in-hand with gaming at higher resolutions, the resolutions that make an SLI configuration desirable in the first place, and unfortunately VRAM doesn't stack when using SLI/CrossFire. The gaming community is somewhat divided on the severity of the issue as no one thus far has conducted extensive testing with more than a handful of games to explore the scope of the problem. If this is enough to put you off on 970s, this article still has value as a GTX 980 SLI build guide; the TDP difference between the two cards is only ~20W.

Package contents.

Zotac has six variants of the GTX 970, the smallest of which was used in a couple of our gaming builds already, but its paltry stock cooling solution forced us to resort to third party solutions. This time Zotac provided us with a pair of their top-of-the-line GTX 970 AMP! Extreme Core Edition cards. This is one of the pricier variants on the market, but by the looks of things, it's worth the premium. It has a substantial triple fan heatsink and is clocked aggressively at 1228/1380 MHz (base/boost), higher than most competing models, and a significant bump compared to the stock 1050/1250 MHz.

The card.

The cooler bears some resemblance to Arctic's Accelero Xtreme series as it utilizes three fans, copper heatpipes running along with length of the card, and perpendicularly arrayed aluminum fins. This dual slot card is quite long, measuring 30.2 cm (almost 12 inches) across but the most notable physical aspect about this model is its standard slot width. Many variants of the GTX 970 use larger boards or cooling solutions that extend over the edge of the PCB, making them much wider, causing interference issues with some cases.

Back side.

To keep the PCB from bending or bowing from the weight of the heatsink, the card has some armor on the back side in the form of a thick metal plate with ventilation holes.

Case: SilverStone Fortress FT05 - US$185


  • SilverStone Fortress FT02 - US$230
  • SilverStone Raven RV03 - US$140
  • SilverStone Raven RV05 - US$125

SilverStone's Raven/Fortress series of towers have consistently been superior performers for us, making their latest model, the Fortress FT05, an easy choice for housing this build. The second, third, and fifth generation versions are particularly effective, especially for more demanding systems. The combination of massive intake fans and a rotated motherboard tray has been a proven winner in our lab.

A tower case with a standard layout faces a significant challenge when utilizing an SLI/CrossFire setup. The card positioned higher up in the case is subject to extra heat rising up from the card below. The results from our load tests with tradition tower designs have been consistent— the upper card always requires a much higher fan speed than the lower card, usually in the 400~500 RPM range, to deal with this added thermal load. The FT05 design however, orients the cards vertically, so each GPU doesn't affect the other nearly as much. The fans can thus can spin slower, and the machine can operate at a lower overall noise level.

The SilverStone Fortress FT05.

This is the first I've worked with the FT05, but it should produce the same results as the Raven RV05 as they are essentially identical cases aside from the exterior. While the Raven line has molded angled plastic on the outside, the upscale Fortress version has a blocky, monolithic design with a wraparound silver aluminum exterior and a highly reflective accent near the bottom. The only plastic visible is the removable top cover where all the heat exhausts out. Other features include a slim, slot loading optical drive bay on the right side in order to maintain a solid front facia, and a large gap at the bottom of the case to feed the two 18 cm intake fans sitting inside on the case floor. Inside the gap is a removable dust filter magnetically attached underneath the fans.

The top.

The power and reset buttons are located at the top, sandwiching a hidden compartment for the front USB 3.0 and audio ports and the three-speed fan control switches for the stock fans. As the motherboard tray is rotated, the back panel and expansion slot ports are all located at the top. The case is taller than it functionally needs to be in order to accommodate and hide all the cabling that runs in through the back.

Side panel.

One nice thing about this design is the side panels simply drop into place without having to worry about aligning any tabs or slots. Acoustic dampening foam is featured heavily in the FT05, both on the side panels and at various spots inside the chassis.


Rather than front to back airflow, the Raven/Fortress design mandates bottom to top airflow, working with the natural path of thermal convection. The two 18 cm fans blow up over the entire interior, covering both the CPU and GPU area. Unlike most enthusiasts ATX cases, drive support is limited because the chassis is actually rather compact with a total volume of only 46 Liters. There's just a small plastic cage at the bottom/rear for a pair of 3.5-inch drives, while two 2.5-inch models can be placed behind the motherboard tray. In reality, the lack of more extensive storage support is hardly significant for a gaming build, especially in this day and age when there are so many good external storage options.

Behind the motherboard tray.

Both the optical drive tray and hard drive cage are removable, but you may want to leave them in place even if they're not being used, if only to better hide cable clutter. The motherboard tray is rather small with few available points for tying down or covering cabling.

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