Macleodgrant: has a point, when I bought mine back in the day the CPU's was just incorporating ''Hyper Threading Technology'' on the P-4's PC.
Now we have the more powerful CPU's with the Core 2 Duo's and the Quad's as well as the i7 chips that can handle two and three programs running along with plugins simultaneously with no problem.
Although I keep my updates current it dose run smother but mine Melodyne cre8 still suffers minor cracks &pops associated with latency issues.
As I mentioned before that Auto Tune works fine, I just prefer the ''Roland V-Vocal in Sonar 8'' that's Bundled in the Sonar program as a plugin, (Part of the same program) so it runs flawlessly, it's also easer to use and have more features / adjustability. It's the best of both worlds like ''Waves Tune'' Same features and NO iLock required and Auto Tune and Melodyne combined.
Peace & blessings.