Tegra is known for low memory bandwidth.

Googling yields a 6.4 GB/s figure for the single channel LPDDR3 supported by Tegra 3. It doesn't sound like the most likely bottleneck for a CPU benchmark given that those A9 cores plod along at about 1/10 the perf of a desktop chip.

What sort of bandwidth do other mobile chips provide?

edit: Looks more like 1/3 than 1/10, looking at the tests in geekbenchscores. I had the 1/10 figure from looking at Sunspider results (http://forum.beyond3d.com/showpost.php?s=502c8933367f315a17f...).

That's still less bandwidth than any other recent SoC and keep in mind that the GPU is also sharing that bandwidth.

While Geekbench is updated frequently, the actual benchmark code is virtually unchanged since 2.0.0 was released.