Hey there,
Question for the original poster: Did you ever get this resolved, or did the machine ever have any major issues? I have a 2009 8-core 2.26 mac pro with just about the same issue.... it's consistent... 12-22 seconds before the machine chimes.
I know this is a long-since forgotten topic here... it's over 2yrs old, but I have had the same issue with my machine for at least 18 months. I spent 2 hours on the phone with a great AppleCare rep, and he thought it needed to go into a Genius Bar.
I worked at Apple retail at the time of the troubleshooting, so I took it to one store closest to me, and after 3 days they thought the machine was fine... even though it still booted with 12-22 second delays before the POST chime.
The store I worked in at the time said "bring it over here... we'll get it fixed... that doesn't sound right." and after a week, they told me "your machine is fine... it just takes a long time to POST."
Having to work with all these people, I chose not to make a stink about it... but now I'm out of AppleCare coverage and I'm just worried that it might crap-out on me at some point and I'll always wonder if it should have been fixed.
Also, I'm a musician and I do a lot of work in Logic Pro with software synthesizers and samplers... I think it's a little strange that my Macbook air puts up slightly better software synth performance than this tower.
Here's the spec:
8-Core, 2.26ghz Mac Pro (2009) with 10GB of Ram (added 2x 2GB sticks, and all original 6x 1GB sticks are in there. System says they're in the properly moved spots)
512GB OCZ Vertex 4 SSD on bootable PCIe 2.0 card.
Various other SATA drives, including the stock 640GB SATA drive
SonnetTech PCIe USB2.0 card
ATI Radeon 5870 1GB Video Card (bought from Apple to upgrade from stock GT120 card)
Apogee Symphony PCIe audio card.
Here's a synopsis of the different things I've tried to see if the issue persists..
1. Every different possible RAM combo down to 2GB of original memory
2. problem existed even before new Video Card, but swapped back to GT120 as a test. Also booted machine with no video card and controlled it via screen sharing
3. removed all PCIe add-on cards
4. Tried different wall outlets in the house, on and off UPS box, even tried it at a friends house and two apple stores
5. PRAM & SMC resets galore
6. Booting from multiple different drives / OS's / Netbooting / Boot from Snow Leopard DVD
7. voodoo and juju magic, prayer,... I stopped short of a "fonzie-fix".
...but the slow boot chime was identical under all different tests.
Machine passed Apple Hardware Tests in two Genius Bars.
Anyone.... Beuller?