I don't reboot that often, so it took me a while before I could try it, but my home desktop, also with SSD, gives
user@twen:~/tmp$ time jruby -e '1'
real 0m0.664s
user 0m0.390s
sys 0m0.110s
for a cold boot. Subsequent startups are 350-400ms. Stock JRuby 1.5.6