I've found the debugger equally slow when launching it via the "servers" tab.
There is a new "remote debug" capability in the trunk version of RadRails. Instead of launching a server from within RadRails, you can start your server externally (on the same or a different computer) under the control of debug-ide and then attach to it from a debug session in RadRails.
I've been using this capability, and found that it also solves the "slow debugger startup" problem.
Not sure why, and I wouldn't have expected it, but it's what I've observed.
