Andrew> ARM9's come in different flavours. Some as slow as 33MHz, others clocked faster. The one depicted at the top of this page is an Atmel AT92RM200 some of which manage around 200Mips performance (putting them in or around StrongARM performance). ARM's site says that some ARM9's manage 300Mips (around Kinetic performance?). Some ARM9's do have the Vector Floating Point (VFP) fitted and can do 200+MFlops (but I am not aware of any RISC OS variant that supports that).
And then there's the big inponderable which of the many variants of ARM9 have STD chosen - their webpage does not detail the type or performance.
It probably wouldn't make a whole lot of sense fitting an ARM9 to a RPC as (for integer performance) the improvement would - at best - be negligable. If the VFP option were exploited that might be of benefit - but it is not compatible (at the moment) with the FPE (so again unlikely to bring immediate benefit).
It is more the principle that ROL can now provide a RISC OS variant for processors currently unsupported and 32bit *only* that is the significant news and that *does* open the possibility of using xScale and ARM10 (or ARM11's when they become available). Even at that these would be best exploited in new hardware as some of the performance issues of the RISC PC simply *won't* be addressed by just changing the processor there are other bottlenecks too....