No 1080p option in nVidia / ATI control panel!

Guys, I have my onkyo TX-SR 605 receiver connected to my HTPC running ATI 5850 card and connected to my Infocus IN72 projector (480p but can accept incoming 1080p) all through HDMI. Anyways, when I try to set the resolution on the HTPC, I only got the choice for 1080i at 30Hz. There was no option for 1080p in the HDTV resolution section of the ATI control panel or Windows 7 control panel. The panel also recognizes the receiver as Onkyo TX-SR605 as the display device but does not show the projector. I don't know if this is normal.

However, when I set the resolution to 720P it works great. 1080i @ 30Hz also works though is not as good. I tried connecting with another HTPC (ASRock Vision 3D with a nVidia GT425 card) and this also did not give me the option of 1080p.

I went back to my old HTPC and then added a custom resolution of 1920x1080p at 60Hz in the ATI Catalyst Control panel and then suddenly the option became available. Though Windows looks washed out at the resolution, movies play great as usual and my projector also shows the incoming resolution as 1080p @ 60Hz.

Any reason why Windows alone looks washed out at this resolution compared to 720p? And why was this 1080p option not available by default for both the HTPCs? Anyone else has gone through with this?

P.S. Sorry if I have rambled a bit, just wanted to describe the situation clearly. Also, I have posted this on the onkyo 605 owners thread, so sorry for the double posting.

Well, according to InFocus's website, its fully compatible with 1080p/60Hz. Here's the link: https://portal.infocus.com/support/P...=IN72&on=specs

And if the EDID is being passed on, then why 720p and 1080i are available but not 1080p?

Another thought just struck me - I use HDMI -> Cat5 baluns to connect the receiver to my projector (due to the distance and bends in the wall, floor and ceiling). Are they causing the 1080p non-availability? But that should be impossible because its all digital, right? It should be either all or nothing. Because I'm getting superb 720p signal. And 1080p after extensively fiddling with the settings.

So let me understand this. You're saying that because my projector is 480p, any type of scaling by the projector will only result in loss of quality, so I should run the HTPC at 480p ideally. The HTPC will scale 1080P content down to 480p and will transmit it to the projector which will display it without any alterations. Am I correct?

The way I'm currently doing is running my HTPC at 720P, and downscaling 1080p content to 720p and transmitting them to the projector which is again downscaling it to 480p. So you're saying that this is worse than the alternative above? Which means that I should ideally have a 1080p projector to avoid all these scaling issues.

Does a 1080p projector make such a big difference compared to a 480p projector - big enough to spend $1000? This may be the wrong forum to ask this question, but any answers will be appreciated!

Thanks for your replies guys. The reason why I never seriously contemplated an upgrade was because my InFocus IN72 is a stunning projector, to say the least. Even though capable of only 480p, the picture quality and sharpness is very "theatre" like and I never felt the need to upgrade, atleast till now. I need to find a way to compare the IN72 with a 1080p projector side-by-side to know the real difference.