If RAM access is needed ARM machines usually fall behind quickly, since they usually have much lower RAM bandwidth.
Comparing with something from 3.5 years and 3 generations ago is useful?
You are right that the i3 CPU(Core i3-530) we compared with is a little old generation. I tried to compare online Core i3-530 with Core i3-2105. The 2105 is SandyBridge(couldnt find a direct comparison with an Ivy Bridge) and runs at a slightly higher clock 3.1 GHz(while the 530 runs at 2.93 according to CPU world).
According to cpu-world. The 2105 is 21% faster than the 530 for single threaded operations. If you account for the speed in clock this would mean only a boost of 14% improvement over the 530.
So its really not such a bad comparison.
In the meanwhile we will try run this on a newer CPU and let you know the results.