Are you sure the other machine isn't mining with a GPU?
I doubt a cpu can reach 50Mhash/s...
OK, I suppose now you say it I'm not *sure*. But this is what I can tell you:
- I'm using GUIMiner with "Ufasoft CPU miner" as the miner
- I'm using that because when I try to use one of the supposed GPU miners I'm told "no OpenCL devices detected"
- detected or not, the machine actually has an "ATI Mobility Radeon HD 5650"
- the miner is definitely using CPU-- this is obvious from the task manager, and from general behaviour (e.g. specifying only 1 or 2 threads makes the CPU turbo faster, which is what the i7 is supposed to do if just a few cores are given extra load). Whether it's using CPU *and also* the GPU, I suppose I'm not sure... Does anyone know about "Ufasoft CPU miner"...?