It's a standard low speed L1A (made in Japan). I can't remember the full manufacturing code off hand, but it's the same one a lot of people around here use.
Yes, the Xbox has overheat protection and that sounds like what you've experienced. When you say "out of the box" I presume you mean the fan set to exhaust? This is the correct way. If you set it as an intake fan the hot air will circulate within the case and heat up, so it's not a good idea if you only have one fan.
My Panaflo is connected to the standard fan header (7V) and set to 70% speed in XBMC, so it is still quiet and just about cool enough. The Xbox does run quite hot but I don't think you need to 12V it, especially if you are concerned about silence.
When I said 'out of the box'..I literally meant outside it to see how fast it spins and how much noise it produces. So it's really no surprise the Xbox shuts down.
One thing I was wondering about..is there an app or something outside of XBMC that can speed set the fan? It's very useful in XBMC, but as soon as you exit it, the fan goes back to the standard 20%. In the case of the SilenX this IMO is too low. I kept an eye on the temps in XBMC with the SilenX inside and running at the standard 20% speed and it went up to 70C+, too high as far as I'm concerned. If you could set it for every app at say 60% I think the temps would be acceptable.
- from a quick google the setting appears to be in the bios, I will have to dig around to find out more
I'll take a closer look at some of the Panaflos, looks like it's on this site
I'll also widen my search to see what else may be acceptable at 7V...expensive fun this
- I think there must be some holy grail fan out there somewhere for the Xbox...it's just a case of finding it!
The irony is the quiet fans are too slow @ 7v to keep temps down to an acceptable level, and @ 12v they are too (relatively) noisy for SPCR types
So what's the answer....not sure yet...but if necessary I'm going to keep buying fans (with reason) and testing them (prior to getting the hacksaw out again) and then deciding which is best.
On brief shortlist at the moment are Papst, Vantec and Panaflo..but if anyone wants to pool info resources that would be helpful.
Ok...not cheap..but once I've cracked it I'll have the best going and the rest will be appearing at an auction site near you (one careful owner)