IIRC, the Asus CUSL2-C (using the onboard Asus ASIC) reads the CPU temperature from the internal temperture diode of newer Intel CPUs. Does the Soyo do the same, or is the temperture read from the external sensor attached below the CPU in the socket on some (older?) motherboards? The higher MHz is of course a factor as already mentioned...if the Asus temp is under load then it seems fine to me. If that's idle, it seems somewhat high, but well within spec.
Edit: With a p3v4x and 600EB, I get 29C idle; don't recall what it was under load.