The Myths Of Graphics Card Performance: Debunked, Part 1

Graphics Card Myth Busting: How We Tested

Two Systems; Two Purposes

All of today's tests are performed on two separate rigs. One plays host to an older Intel Core i7-950, and another based on Intel's Core i7-4770K.

The first test system needed to facilitate repeatable results in a real-world environment. So, I set up a relatively old, but still very capable LGA 1366-based machine in a full-tower enclosure.

Test system number two needed to fulfill more specific requirements:

1. Support PCIe 3.0 with a limited number of lanes (an LGA 1150-equipped board with a Haswell-based CPU, which only offers 16 lanes)
2. Do not employ a PLX bridge chip
3. Support three-way CrossFire in x8/x4/x4 or SLI in x8/x8 configurations

ASRock sent us its Z87 Extreme6/ac, which fit that description. We previously tested this board (minus the Wi-Fi module) in Five Z87 Motherboards Under $220, Reviewed, where it received our prestigious Smart Buy award. The sample we received was easy to set up, had no problem overclocking our Core i7-4770K sample to 4.6 GHz.

The board's UEFI gave me the option to set PCI Express transfer rates on a slot-by-slot basis, which enabled testing of PCIe Gen 1, 2 and 3 on the same motherboard. You will see the results of these tests in part 2 of this article.

Cooler Master supplied the second test system's chassis and power supply. The unconventional HAF XB enclosure, which also received Smart Buy honors in Cooler Master's HAF XB: Give Your LAN Party Box Breathing Room, proved comfortable to work with. It's very open, of course, so the components inside can get noisy if you don't have the right cooling setup. The case benefits from good airflow though, particularly if you hook up all of the optional fans.

The modular V1000 power supply allowed us to drive three high-end graphics cards, while containing cable clutter in a setting that was destined to get messy.

Comparing Test System 1 And 2

It's striking to see how similarly these systems perform once we get past their underlying architectures and focus on their frame rates. Here's a head-to-head between them in 3DMark Firestrike.

As you can see, the performance in graphics tests is essentially the same, even though the second machine has faster system memory (2133 versus 1800 MT/s, counter-balanced by Nehalem's triple-channel architecture compared to Haswell's two channels). Only in the host processor-dependent tests does the Core i7-4770K demonstrate an advantage.

The second system's main advantage is more overclocking headroom. Our Core i7-4770K sits at a stable 4.6 GHz on air, while the Core i7-950 can't exceed 4 GHz cooled by water. 

It's also worth noting that the first test system is benchmarked using Windows 7 x64 instead of Windows 8.1. There are three reasons for this:

• First, the Windows desktop manager (Windows Aero or wdm.exe) uses a significant amount of graphics memory. At 2160p, it ties up an additional 200 MB in Windows 7 and 300 MB in Windows 8.1, on top of the 123 MB already reserved by Windows. This cannot be disabled without significant side effects in Windows 8.1, while it can be disabled in Windows 7 by switching to a basic theme. Four hundred megabytes is 20% of a 2 GB card's memory.
• The memory usage in Windows 7 is consistent with a basic theme enabled. It is always 99 MB at 1080p and 123 MB at 2160p on a GeForce GTX 690. This makes for more repeatable tests. In contrast, the additional ~200 MB of memory used by Aero varies up and down by roughly 40 MB.
• As of Nvidia's 331.82 WHQL driver, a bug exists affecting 2160p when Windows Aero is enabled. This only surfaces when Aero is enabled on a tiled 4K display, and it manifests itself as lowered GPU utilization during benchmarks (bouncing in the 60-80% range, instead of close to 100%), and a resulting drop in performance of 15% or so. Nvidia was notified of this.

Tearing and ghosting effects do not show up in regular screen shots or game videos; I used a fast camera to capture the actual on-screen image.

Case ambient temperature is measured with the Samsung 840 Pro integrated temperature sensor. Background ambient temperature was in the range of 20-22 °C (68-72 °F). Background sound pressure level for all noise tests was 33.7 dB(A), +/- 0.5 dB(A).

A variety of tools can be used for measuring graphics card memory use. We went with HWiNFO64, taking advantage of its maximum mark. The same results can be obtained through MSI Afterburner, EVGA Precision X, or simply the RivaTuner Statistics Server stand-alone.