My understanding is, 3750s can provide their rated Mpps (series max, 38.7 Mpps) for routing traffic as long as the traffic is processed in the fast/CEF path (and processed by their ASIC hardware). I haven't seen a performance rating for their process switching.
Software router process switching is often 10x or more slower than fast/CEF path. For 7600s with sup720, fast/CEF path is 15 or 30 Mpps but process path is only 20 or 500 Kpps, an even larger difference.