PowerColor Radeon HD 6970 LCS Review

ccokeman - March 3, 2011
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Testing:

Testing of the PowerColor HD 6970 LCS will consist of running it and comparison cards through the OverclockersClub.com suite of games and synthetic benchmarks. This will test the performance against many popular competitors. Comparisons will be made to cards of equal and greater capabilities to show where they fall on the performance ladder. The games used are some of today's newest and most popular titles to give you an idea of how the cards perform relative to each other.

The system specifications will remain the same throughout the testing. No adjustment will be made to the respective control panels during the testing, with the exception of the 3DMark Vantage testing, where PhysX will be disabled in the NVIDIA control panel. I will test the cards at stock speeds, then overclocked in order to see the effects of any increases in clock speed. The cards are placed in order from highest to lowest performing in the graphs to show where the cards fall by comparison. The Powercolor HD 6970 LCS will be put into an existing water cooled loop simulating what you normally find with a high to mid-range system.

Processor: Intel Core I7 920 200x18 3.6GHz
Cooling: Noctua NH-U12P SE 1366
Motherboard: ASUS P6T Deluxe OC Palm Edition
Memory: Mushkin 996805 Redline PC312800 6-8-6-24 1600MHz
Video Card: PowerColor HD 6970 LCS
Power Supply: Mushkin 1000 watt Joule Modular power supply
Hard Drive: 1 x Seagate 1TB SATA
Optical Drive: LG DVD-RW
OS: Windows 7 Professional 64-bit
Case: Cooler Master HAF 932

Comparison Video Cards:

Overclocking:

PowerColor HD 6970 LCS 1021/1520MHz

When overclocking a video card or CPU, heat is most often one of the barriers to increasing the core clock and memory speeds. There are many ways to pull this heat from the CPU or GPU from air to Ln2 or a simple water cooling loop. PowerColor has gone the water cooling route with this offering and the clock speeds it was able to hit are a testament to the fact that water cooling helps increase the clock speeds that are attainable by keeping temperatures in check. As delivered, the LCS comes with a 925MHz clock speed on the core that is within 25 MHz of the highest clock speeds I have been able to reach on a reference based HD 6970. That being said, I had expected to top out in the 970MHz range but easily shot above the 1GHz mark with a tweak to the voltage up to 1.270v. Sure that may seem high to some but in games the temperatures never reached above 45 degrees Celsius in the water loop in the test setup. That is the reason for a liquid cooled card right there. Ultimately the clock speeds reached 1021MHz on the core and 1520MHz on the GDDR5 memory. This represents an overclock of around 10% on the core and roughly 6.5% on the memory. These improved clock speeds offer up increases in gaming performance that you would not be able to get with a reference cooled card.

Maximum Clock Speeds:

In the past, I had used MSI's Kombuster utility to check for stability coupled with the ability to run through the entire test suite. I have found that some game tests would still fail with this utility, so I have moved to testing with several games at maximum settings through several resolutions to verify the clock speeds that are listed below. Why the change? I have found some cards will play fine at a 4xAA setting, but fail when using 8xAA due to the increased graphics load. If it fails, then the clock speeds and tests are rerun until they pass.