If that's the case then I've been misunderstanding Thumb all this time. My understanding was that Thumb instructions are slightly less efficient than ARM. The real benefit of Thumb is that the compiled binaries are smaller and thus take less memory space and require less swapping. In other words, any given binary will not really benefit from being compiled as Thumb, especially if it is a CPU-intensive one. Thumb is more about being nice to others: I sacrifice a percent or two of my efficiency to make you running smoother (less swapping).

Please correct me if I got it wrong.