Roger Pack wrote: > which version of ruby-prof? ruby-prof-0.7.3-x86-mswin32-60 I've just tried again set RUBY_PROF_CPU_FREQUENCY=1 782 411 428 (1.66*1024*1024*1024) then ran C:\InstantRails\rails_apps\projectN>"ruby-prof" "--printer=graph_html" "--file=ruby_prof.rake.html" "--min_percent=1.00" "--mode=cpu" "--" "C:\InstantRails\ruby\bin\rake" --tasks got about 105 seconds then set RUBY_PROF_CPU_FREQUENCY=178 241 142 (previous value/10) and got about 110 seconds -- Posted via http://www.ruby-forum.com/.