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...).