I posted this to another similar post but didn't get a response from JetBrains.
Re: Rubymine Debugger Painfully Slow
I'm having the same problem. Just upgraded from 5.4.2 to 6.0.3. Formerly, debugging the exact same file (a plain old ruby file, no rails), was instantanious. Now, it takes 20 seconds to 3 minutes, PER LINE of code! It is unusable. I have been using puts statements to debug because the debuger is literally unusable now. I thought there might have been a conflict with the old project file, so I created a brand new project. Same effect.
Please help. The debugger is the main reason I purchased RubyMine and now I cannot use it.
BTW, the editor is much faster in 6.0.3 and the code completion works now for the first time.
I also updated ruby-debug-ide as part of the install. And I just ran gem install ruby-debug-ide to make sure it was up-to-date. No effect. Debugging is still unusable.
Using ruby ruby 1.9.3p194 (2012-04-20) [i386-mingw32] on Windows 7 Ultimate 64 bit. Machine is fast. And, as mentioned above, older versions of RubyMine debugged with quick reponse times, for the same source code files that now are absurdly slow.