I used palm internals for speed tests, my treo with all programs installed except a mp3 ringer is 5 secs.
Ran all latest versions of ringer apps.

Mring 2.8: really like that you can define a ring volume for each contacts and also assign vibrate to each contact individually. Easy setup as contact list is already in program. speed results:60 secs

Lightwav 5.6.1: zipcode info and unknown caller filter real nice. Also allows you to assign a tone in ram, midi or mp3, to use when/if your SD card is missing. similar setup to ringo, contact lookup. speed results:60 secs

Ringo Pro 4.394:basic..contacts lookup for indiv ringers. If you use a mp3 for your 'default ringtone' it copies a 256k chunk of the song into ram, only for that tone all others remain on Sd, if that's where you had them. Speed test 5 secs

I used each for a week with no resets or other probs.

I'm sticking with Ringo pro with RNS's TAC for zipcode lookup, for now....