The 81/110 is based on the Apple 8100/110 board. Unlike the Apple 8100/110's, the Radius boards use a surface mount oscillator, so they are even easier to clock chip. To clock chip it, you can follow modification 1 or 3 as outlined in the Mac Crystal Oscillator Speedup History 2.5 File. The max stable speed is around 126MHz. Just like the Apple PM8100/100 and PM8100/110, the 81/110 has a single stack peltier solid state cooler on the PPC601+ processor. There is adequate cooling, so no extra fan is necessary.
There is a set of Speedometer 4.02 benchmarks for the Radius 81/110 on the Speedometer 4.02 Files page.
If you are interested in running Sound Manager 3.1, take a look at the Sound Manager 3.1 Incompatibilities page.