AMD Radeon HD 7970 3GB Review

Author: SKYMTL
Date: December 21, 2011
Product Name: Radeon HD 7970 3GB
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GPGPU Performance; OpenCL & DirectCompute

Like many other modern GPU cores, Southern Islands has been designed from the ground up to provide exceptional compute performance. With dual DMA engines that have the capability to saturate the PCI-E 3.0 bus and a highly parallelized Graphics Core Next architecture, it is no wonder why AMD has been talking up these cards’ advances in this field.

In order to put some of these claims to the test, we used a number of synthetic OpenCL and DirectCompute benchmarks with all cards running on a PCI-E 3.0 slot. In order to cut the CPU out of the equation, we focused strictly upon stressing the shaders.

First up in our testing regimen was LuxMark, a simple benchmark that uses an OpenCL calculated ray tracing routine to render a highly complex scene. As with many of these benchmarks you will see in this section, its results are largely theoretical but could be replicated if programmers choose to implement highly optimized OpenCL code into their applications. With that being said, the HD 7970 walks all over its predecessor by posting a 65% improvement.

SISoft’s Sandra platform is a one stop shop for benchmarkers and a simple OpenCL engine was recently included and later perfected. As with LuxMark, it can truly show the Tahiti XT’s potential in compute tasks and how much this architecture has improved over the previous generation. To put this into perspective, the HD 7970 has only about 35% more compute units than a HD 6970 but its performance has more than doubled in some cases.

For DirectCompute performance, we used a number of different benchmarks ranging from some typical Mandelbrot sets to more complex 3D dynamic fluid calculations. All of the scenarios were measured in frames per second using FRAPS over a 3 minute period for each.

Again we see some eye opening improvements from one generation to the next and this time the differences between new and old is significant. The HD 7970 is really able to stretch its legs in some of the more complex scenarios.

Unfortunately, we couldn’t get any Folding@Home numbers for this review since Stanford’s new V7 beta GPU client (which supports OpenCL) failed to recognize our card. Hopefully this will be rectified in the next release since as we saw above, the HD 7970 has the potential to be a Folding powerhouse if the OpenCL coding can be successfully ported over to the GCN architecture. Until then, we’ll continue looking for some real world applications that can highlight the benefits of OpenCL and DirectCompute performance.

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