Apple A5 Processor (iPad 2) Smokes NVIDIA Tegra 2 (Motorola Xoom) in Both CPU & GPU Performance

Submitted by lalit on March 19, 2011 - 2:33pm.

When Apple started designing their own ARM processors for iPad and iPhone, many questioned if they will be able to compete with companies like NVIDIA and Qualcomm, as these companies have more resources and experience in chip development. Apple started with A4 processor based on ARM Cortex-A8 CPU, which was one of the best ARM processors available in 2010 and kept iPhone ahead in the smartphone race. But by Q3 of 2010 other companies started showing dual core ARM Cortex-A9 based chips like Tegra 2 and Snapdragon, and again the same question was raised, as Apple wasn’t providing any information about what chip they have in store for 2011.

After launch of iPad 2, we now know that Apple was working hard on A5 processor, as it is one of the two dual-core ARM Cortex-A9 based processors that are actually shipping. So, now the main question, is Apple’s A5 processor able to compete with processors from other companies?

NVIDIA’s Tegra 2 processor was one of the most talked about dual-core ARM processor when it was announced last year because of its GeForce GPU, which some considered best in graphics. And it’s only natural to compare it with A5 processor to get an idea where Apple stands. Many reviewers have compared performance of Motorola Xoom (Tegra 2) and iPad 2 (A5) in their reviews and have posted benchmarks showing both the CPU and GPU performance of the new chips.

Both A5 and Tegra 2 are based on dual-core ARM Cortex-A9 CPU running at 1GHz. However, when you look at performance there is quite a difference in both the chips as shown by LINPACK tests. Ars Technica ran the LINPACK test on iPad 2 and Motorola Xoom, and were surprised to see iPad 2 outperforming Xoom tablet by 336%. LINPACK test measures floating point performance in FLOPS (Floating point Operation per Second) and it gives a true picture of computing power offered by CPU. As you can see in the graphics iPad 2 scored 160.8 megaFLOPS whereas Xoom scored just 36.8 megaFLOPS.

Ars Technica wrote, “the only factor we can think of that would explain such a boost in LINPACK performance vs. both the original iPad and rival Tegra 2-based devices is that A5 must have full support for ARM's NEON vector extensions (the ARM equivalent of Intel's SSE instructions). The NEON extensions, along with the larger vector FPU (VFPU) to support them, are included by default in the A8 family, but are optional in the A9. NVIDIA's Tegra 2 opted for the smaller, lower-power, but weaker ARM FPU, while Apple seems to have included the beefier NEON VFPU in their implementation of the A9. Clearly this is the way to go, and we can expect other ARM SoC vendors to follow suit.”

Apple won the CPU battle, but what about the GPU performance where many believed NVIDIA's expertise in Graphics would give them an edge over Apple. Tegra 2 has GeForce GPU, whereas A5 chip uses Imagination Technologies’ PowerVR SGX 543MP2 GPU. AnandTech compared performance of both the GPUs using GLBenchmark 2.0 and saw that iPad 2 outperformed Xoom by at least a factor of two in most tests. In not a single test Motorola Xoom topped iPad 2. In two geometry throughput tests – textured triangle test and fragment lit triangle test – iPad 2 scored 29 and 19.7, whereas Xoom scored 15.1 and 8.51 respectively. In texture fetch test the difference was more drastic iPad 2 scored 890.1 compared to Xoom’s 130, over 6x difference in performance.

To get an idea of real world performance difference, AnandTech ran GLBenchmark 2.0 game tests. Egypt test on iPad 2 run at 44 frames per second in comparison to 11.8 frames on Xoom, 3.7x faster. In the GLBenchmark 2.0 Pro test also A5 processor on iPad 2 offered over 2x the performance when compared to Tegra 2.

In both CPU and GPU performance Apple’s A5 processor left NVIDIA’s Tegra 2 in the dust, performing at least 2x faster and sometimes even 5x faster. So, the answer to the initial question – Apple is not only able to compete with other chipmakers, but as of now they have the best ARM dual-core processor on the market. And the bad news for other smartphone and tablet makers is that only Apple products like iPad and iPhone will have access to A5 processor.