Testing - Temps, Voltages, Acoustics, and Overclocking
|CPU||Intel Core i5-3570k|
|Motherboard||ASUS P8Z77-V Pro|
|GPU||ASUS HD 7970 DirectCU II|
|RAM||Kingston Predator 16GB (2x8GB) 1866MHz|
|CPU Cooler||Cooler Master Seidon 240M|
|Thermal Paste||Noctua NT-H1|
|Primary HDD (OS)||Patriot Pyro 60GB SSD|
|PSU||OCZ Fatal1ty 1000W|
|Chassis||Fractal Design Define XL|
|OS||Windows 7 Professional 64-bit|
We ran a variety of benchmarks to evaluate how the ASUS HD 7970 DirectCUII performs alongside several other mid-range graphics cards we've previously had on our test bench. Each benchmark was run a minimum of 3 times, and if greater than 10% variability was seen between runs, additional runs were conducted to ensure variability was eliminated across a wide number of runs. We tested each game at maximum settings (including maximum AA and Ambient Occlusion) at 1080P and WQHD (2560 x 1440) resolutions.
The 7970 DCUII was tested on the beta 13.2 drivers provided by AMD which have optimized performance for newer games we tested with, like Far Cry 3. All other comparison cards were tested with the latest game-optimized drivers, unless otherwise noted.
The following applications were used to benchmark a wide variety of graphical engines from DX9 to DX11:
-Far Cry 3
-Dirt 3 Benchmark Tool
-Batman: Arkham City Benchmark Tool
-Aliens vs. Predators Benchmark Tool
-3DMark11 GPU Benchmark Suite
-Unigine Heaven 3/4 Benchmark Tool
Overclocking - Temps, Noise, and Voltage
Newer builds of ASUS' GPU Tweak software limit the maximum voltage increase of the HD 7970 (a new build will be coming soon to open it back up), and you must use GPU Tweak version 2.1.14 in order to unlock your otherwise locked voltages. With that said, we first started out overclocking with the locked voltage range, which limited us to 1.120V, a mere 10mV higher than the stock voltage, which has lead many users to believe their voltage is locked on a hardware level. While it's a bit confusing at first, version 2.1.14 of GPU Tweak is the simple answer.
We expected our first overclocks to be underwhelming, as we're essentially trying to push the card at stock voltages. However, we were very pleasantly surprised, as our card hit a 25% overclock in stride at 1.120V. That brought us to 1160 MHz on the GPU clock and 7000 MHz (1750 MHz actual) on the memory. That's nothing short of impressive. Under load we were seeing maximum GPU temperatures only 71°C. Better yet? The maximum fan speed was only 37%, and given the large, low-RPM operation of the DirectCUII's 100mm fans, that equates to a gentle hum barely audible outside of our acoustic-friendly Define XL case. That's fantastic performance for a beast of a card capable of powering through surround 3D gaming with relative ease. As this represents a very basic, attainable, conservative, and acoustically-pleasant overclock scenario, we used this as our overclocking benchmark in our benchmark suite in the following pages, intending to be a representative data point that any customer should be able to come close to matching (and the performance they'll see).
Using GPU Tweak 126.96.36.199 to unlock a voltage range that goes to 1.4V, we found that the card generally responded with instability at anything above 1.250V. Cranking up the fan allowed us to increase the voltage to about 1.275V, but it didn't allow us to bump up the GPU Core or Memory clocks any further. Our best OC we were able to crank out was an impress 1180 MHz on the GPU Core and 7100 MHz on the Memory. This was possible with the default fan ramp and we didn't see the fan duty cycle go above 45% or the temperature above 75°C and acoustic levels were still impressive, producing nothing more than a low hum.
Overall, it was impressive how much of the maximum air-cooled OC potential we were able to squeeze out of the 7970 DUCII with a limited voltage range, getting us most of the way (1160/7000 MHz) of the max of 1180 MHz on the GPU core and 7100 MHz on the memory. The overall overclocking headroom of almost 30% that we were able to tap adds a lot of extra horsepower for you hard-earned dollars.
While we talked acoustics somewhat above, this is, in my opinion, one of the strongsuits of the 7970 DCII, and so we'll delve into it a bit again here. At idle and during normal usage, the noise coming from the card is indistinguishable from the other fans in our case. Under load, we never saw the fan duty cycle go above 50% while maintaining mid-70 degree Celsius temps, and at about half fan speed the card noise is little more than a low-frequency hum, and lacks the truly-obnoxious high-pitch whine of smaller, higher RPM fans and impellers. At full speed, the whirl of the fans becomes very noticeable as the noise frequency goes up, but the thermal dissipation capacity is very high at full speed for those who aren't putting acoustic performance as a priority. The bright side is that we had the ability to apply nearly a 30% overclock without a noticeable increase in system noise. An auxiliary acoustic concern that is often overlooked is that the fully-sealed inductors essentially eliminate any inductor coil whine which may be an annoying side effect of VRM design.