Hmm. Well, yes, sortof.

I say "sortof" because if you haven't run for awhile on a RAID0/striped
array...THEN switched to RAID1...you won't have a point of reference against
which to compare the performance [decrease] of a mirrored array.

Is a striped array faster than a mirrored array? Absolutely. But as you
already know, the latter is safer.

That said - and I know there are those that disagree - my counsel would be
to go with the RAID0. The likelihood of a failure on one out of two drives
which are in a RAID1 array is still pretty slim. And if the failure of one
of those two drives ends up taking 2 years...then you will have lost out on
the significant performance boost offered by a striped array for 2 years. A
bit like buying insurance, eh? You just pay your price; just in case.
Except in THIS case, a failure means a bit of time to re-install software,
not a loss of life. Besides, if you set up a striped array, you can always
maintain a clone of the array on a separate drive in the system!

Please post a follow-up.
Ron