I need to time one of the latest ones we have, but as far as I remember, even they are faster than a certain company's servers, and Intel's reference/development servers.
Both were booting in 5+ minutes under normal circumstances.
I bet its between 3-5 with the Dells. Its long enough that I often have that sinking feeling after issuing a reboot where I think its hanging and I'll need to make a trip to the data center...just to finally breath a sigh of relief when I see that 'ssh connection closed' message as it finally gets into the linux boot sequence.