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Can OpenGL And OpenCL Overhaul Your Photo Editing Experience?

Benchmark Results: AfterShot Pro

As we indicated earlier, Corel was kind enough to supply us with a tech preview of AfterShot Pro featuring OpenCL support. The company really went out of its way to accommodate us, and we’re grateful. Up to present, AfterShot has focused on CPU-based optimization, as described by Jeff Stephens, head of product development for AfterShot Pro and former president of Bibble Labs.

“In AfterShot Pro 1.0, there is zero GPU utilization,” says Stephens. “Years ago, Bibble Labs, which Corel acquired about one year ago, decided to focus on multi-core processing instead of relying on graphics processing. That decision paid off for years. Bibble 4, followed by Bibble 5, and now AfterShot Pro have been and are the fastest RAW conversion applications we've ever tested or seen. That's true not only on a single CPU, but as the user adds CPUs, our scaling is very near linear up to eight CPUs and continues to excel to up 16 cores and beyond. What OpenCL is allowing us to do is to squeeze up to a 2x performance gain out of existing computers by utilizing the GPU that was otherwise idle while continuing to fully utilize as many CPU cores as are available.”

As promised, Corel squeezes twice the performance from our test systems when using GPU acceleration compared to running only through the CPU in software. Actually, OpenCL bestows just over a 100% benefit.

You might notice how our A8-based desktop platform's results are nearly identical, regardless of whether we use the APU's shader cores or a discrete Radeon HD 7970. Sound familiar? But before we jumped to the same conclusion regarding a bottleneck, we went back to Corel with our findings. Working with a platform very similar to our A8 configuration, Corel reported 27.35 seconds using OpenCL and the Tahiti-based 7970 (as opposed to our 32.02) and 36.30 seconds with OpenCL on APU (as opposed to our 31.50). That seems much more in line with expectations. Unfortunately, after confirming identical BIOS builds, driver versions, OpenCL versions, and everything else we could think of, no amount of persuasion would shift our numbers significantly, so we had to publish our own results. Caveat given. Your mileage may vary.

The nature of our preview build of AfterShot Pro resulted in our HP notebook kicking out a “program can’t start because OpenCL.dll is missing” error, and the program would not start—hence no HP/Intel results in this benchmark.