For many PC users, "integrated" chips are synonymous with lower performance. This perception perhaps remains from the days of northbridge-based graphics, which were mediocre even on the best days. Most likely, that stigma will soon vanish. We don’t have the side-by-side data to show how CPU Die X performs in both APU and graphics-free versions. But it seems safe to say that in a heterogeneous environment, leveraging software designed for APU-type processing, an APU will deliver better total performance than if those CPU and GPU cores are separated into discrete components. If the APU paradigm wasn’t inherently better, the entire industry wouldn’t be shifting to it so rapidly.
Testing at Tom’s Hardware shows that, in a toe-to-toe battle between AMD and Intel, just looking at x86 performance, Intel is today’s clear victor. Far less clear is what happens once heterogeneous graphics are factored in. Just as Intel has the stronger CPU, AMD obviously has the stronger graphics architecture. What happens when the software running across these platforms takes fair and ample use of OpenCL and other heterogeneous architectures? That’s what our ongoing heterogeneous compute series is looking to answer.
"Today," says AMD’s Hegde, "the CPUs in our APUs may be lower in performance in your tests against Intel. But that’s not an indication of where we are going. We’re now embracing the low-power space in a very strong way, so we are building CPUs that are going to have very good performance with a very low power envelope. So when we say ‘balanced platform,’ we’re not saying that you have to take one or the other. We’re saying that, in a balanced platform, for every workload, do it in the place that makes the most sense. Intel’s approach of doing everything on the CPU is just wrong, because when you put a balanced workload on just the CPU, your power draw is dramatic and unnecessary. That’s why we don’t think that’s a good model. We’re going to make the cost of transition from CPU to GPU next to nothing. Then it’s up to each application to choose the right execution engine in terms of performance and power."
Similarly, AMD feels that HSA may be its path to success in smartphones and tablets, because when applications are properly optimized for balance, the GPU becomes much more influential in determining battery life. HSA targets two things: ease of programming and performance per watt. Once GPGPU compute comes into play, analysis shows that the GPU is 4x to 6x more performance per watt efficient than a CPU. ARM may have the biggest piece of that heterogeneous smartphone opportunity, but AMD is betting there’s still plenty of room for a strong number-two player who just happens to be using the same programming architecture as ARM. As mentioned, the implications for Nvidia and ultramobile would-be contender Intel are significant.