I have a 1080p projector (Epson 1080UB). If I connect DVI to HDMI cable directly to it from my iMac 2.8GHz Core 2 Duo, it allows 1080p60. However, I have a 3x1 HDMI switcher. If I go through it, it only allows 1080i. Any ideas how I can force 1080p out. Do I have to use DisplayConfigX or SwitchResX?

I have a similar projector, Panny AE-2000, and I use a monoprice HDMI switch. It was 50 bucks and does not downgrade 1080p signal. I also have bluray and tivohd through the switch.

Hope that helps.

I've heard of people having good luck using a DVI detective.

http://www.gefen.com/kvm/product.jsp?prod_id=4715

Hope this helps,
Kenny

My bad, I also am using the DVI Detective!

I am also using DVI Detective, but beware that some "HDMI" components do NOT support 1080p, only 1080i (the HDMI standard provides the "option" for 1080p support, but does not require it :mad:).
That may be the case of your switcher.
The benefit of Gefen DVI Detective is that it provides the projector EDID to the Mac, even when the Projector is switch off or its connection to the Mac unplugged. This would avoid any rebooting of your Mac just because it believes it has no display attached.