Saving 50 ns on data retrieval never seemed much of a big deal to me.... And launching??? I never have to relaunch my programs. Matter of fact, my system stays up Su-Fr, without reboots. (Guess I can afford the electric bill eh??) Don't know why launching programs is such a big deal. Once it's up, it's up... of course I also perform backups and maintenance when the markets are closed or inaccessible (The ones i trade) Between 7am EST and 8am EST Complete data backup and update. Too each his own. I don't like the heat or the noise. I want to hear my jazz when I trade, not my hard drives.
Raid can present problems when using a recovery disk as well. If I wanted more speed, and currently it would not buy me anything, I'd rather go with the 10,000 rpm and the KISS principle.
Ultimately it comes down to this. Either medium will crash. Did you do your Daily Backups??? I never will forget the lesson I learned from my Old GM at my old Job (when I was 20) Everynight at 5pm they did a Data backup (back then it was to tape.) I never will forget the day the servers went down. That lesson has stuck with me since.
I guess I still don't see your point Gregarious. Yes, using faster drives and RAID will give you faster disk access - who would dispute that? I could just as easily say having more or faster processors will lower your % CPU utilization and adding more memory will lower your % memory utilization. The question is, does a normal trader need faster disk access beyond what a single 7.2k drive delivers? The two examples you gave, faster program startup and better (?) writing of streaming quote data do not convince me. How often do you start a program and are you doing it in the middle of the trading day? What would be the system impact of writing data out using 7.2k drives instead of 10k - do you think your system would be noticably slower? Its easy to advise everyone to get the best, fastest machine that money can buy but I do not think its good advice unless their intended use of the machine really justifies it, in this case I just don't see it.
No. The biggest difference is when loading/saving files, and starting apps. Apps that do tons of file access will see an improvement too.