One issue here COULD be the HDMI handshake. HDMI has a built in anti theft protocol and this means that some verification needs to take place between the TV-circuits and the graphic card on the PC. If the HDMI versions are different (PC/TV) it can generate some problems, in some cases. I haven't read up on this though.
I have an old Sony TV and a new HTPC and my sound always gets a 2 second start-delay, so I hear no system sounds since they are short. I think it just takes my old TV 2 secs to give ok to the PC on the sound. But my boot time is fine (though without logon sound).
There is a lot out there on these handshake problems.
Other tips
1: set your bios to show all the POST messages (instead of logo)
2: boot into windows safe mode to see if it is faster
3: MS used to have a software that logged the time it spent on everything during boot. (bootvis I think it was called)
EDIT: Instead of bootvis you can use WinBootInfo for free for 30 days. Link to article that includes download link:
WinBootInfo is a BootVis Alternative that Works in Windows Vista and 7 | Raymond.CC Blog