For the last 5 years, I've been running a 1280 x 720 resolution at 72 hz from my HTPC with a Radeon LE video card. I used Powerstrip to customize this resolution.

Since I plan to convert my G70 over to digital using a DVI input card, I finally replaced my old video card with a Radeon 9800 Pro, which has a digital output as well as analog. The latest Catalyst drivers (ver. 7.2) allowed me to choose a 1280 x 720 resolution at 60 hz or 75 hz, not 72 hz. So instead of using Powerstrip, I chose the 60 hz refresh rate, and the G70 picture quality is about like it used to be at 72 hz.

But I wanted to try the 75 hz to see if I could see any improvement. When I did, the G70 lost sync at the new frequency (which I suppose I should expect), so I needed to reconverge from scratch - all three RGB guns were way off.

Once in Service Mode, I got a green pattern looking good with good focus, then I started on red. But I got to a certain point adjusting bow to match the green, and the projector shut down with an error code 30. I tried this a few times with the same result. I finally gave up and simply went back to 1280 x 720 at 60 hz.

Error code 30 says its a voltage problem on the DC board. Am I just exceeding the capabilities of the projector? It always ran flawlessly at 72 hz from Powerstrip, but this happens when I try to set it up at 75 hz using the Radeon drivers.

I'm hoping one of you G70 and HTPC gurus might have some comments. I'm OK with running 1280 x 720 at 60 hz, but I'm curious about the limits of the G70. Or perhaps you might have other recommendations?

Thank you,

Ray

Why would you want to run 75Hz if you are in the US?

You really should be set for 71.928Hz for film based stuff and 59.whatever for video, 75Hz will just cause a judderfest for NTSC material.

Why would you want to run 75Hz if you are in the US?

You really should be set for 71.928Hz for film based stuff and 59.whatever for video, 75Hz will just cause a judderfest for NTSC material.

I really don't know why. I was thinking that the higher the refresh rate the better - no?

To try 71.928, I assume I would have to go back to Powerstrip? I use the HTPC for playing back DVDs and sometimes using Windows on the computer.

Apparently I don't understand refresh rates well enough.

I really don't know why. I was thinking that the higher the refresh rate the better - no?

75 is not evenly divisible by either 24 or 30, so you'll have judder on both film and video-based material. On a G70, you should be running 72Hz for film-sourced material and 60HZ for video.

the actual numbers are 24/1.001 and 72/1.001 as well as 60/1.001

Back to one of the original questions..

No, 1280x720 at 75hz is nowhere near too high a res for a G70.

You may have pushed it a little harder than normal, but it should not have failed.

My G70 was running at 720p 60HZ. When I changed it to 864p 75HZ (Pal) it blew the F boards. Replaced the boards and all is OK and has been for a while now. I expect the extra work I was asking it to do highlighted a weakness in that particular board.

Back to one of the original questions..

No, 1280x720 at 75hz is nowhere near too high a res for a G70.

You may have pushed it a little harder than normal, but it should not have failed.

Fortunately, nothing failed. The projector just shut down with a 30 error code. After trying to reconverge at the 75 hz frequency about three times, I just gave up.

I went back to 1280 x 720 at 60 hz and the projector runs great, as it always has.

75 is not evenly divisible by either 24 or 30, so you'll have judder on both film and video-based material. On a G70, you should be running 72Hz for film-sourced material and 60HZ for video.


My G70 runs at 1080i at 60 hz via component video from my Dishnet HD DVR. Since that is "video-based", that sounds OK I guess.

My HTPC is used for DVDs (video-based again?) and for running Windows XP based programs like Internet Explorer, Google Earth, showing digital photos, etc. I used to run at 1280 x 720 at 72 hz (actually, I think it was 71.9 something as someone else mentioned). DVDs and Windows looked fine.

Now, I run at 60 hz, mainly because it is an easy choice from the Radeon Catalyst drivers for the 9800 Pro video card. Is it recommended to use Powerstrip anyway, so I could again run at 72 hz?

On CRT computer monitors, 60hz produces irritating flicker, so I always ran them at 72-85 hz. On my G70, I "think" I may detect a bit of flicker at 60 hz, so that is why I wanted to try the 72 hz again. If the flicker is there, it is barely noticable, but I find it hard to tell without a direct comparison.

(There is no flicker, however, at the 1080i at 60 hz from my Dishnet receiver.)

1080i at 60 hz via component video from my Dishnet HD DVR. Since that is "video-based", that sounds OK I guess.

My HTPC is used for DVDs (video-based again?)
Video-based is sports, news, game shows, sit coms, etc.

For the D* movie channels and for DVDs, you'll still want 47.95 or 71.928 Hz for film-based content.

See Inverse Telecine (IVTC) (http://www.doom9.org/ivtc-tut.htm)... you basically want to undo the 24->60 telecine (3:2) to get back to the 24 film frames... then you double or triple those frames to get 48 or 72.

Video-based is sports, news, game shows, sit coms, etc.

For the D* movie channels and for DVDs, you'll still want 47.95 or 71.928 Hz for film-based content.

See Inverse Telecine (IVTC) (http://www.doom9.org/ivtc-tut.htm)... you basically want to undo the 24->60 telecine (3:2) to get back to the 24 film frames... then you double or triple those frames to get 48 or 72.

Interesting article, but it was pretty heavy! I did pick up some good info though - thank you. :)

I decided to start up Powerstrip and set the frequency to 71.927 (.928 wouldn't take). I reconverged the G70 and it looks good.

Quite honestly, I don't know if it looks any better, but I'll leave it there.

I still don't know why the projector gave me an error code 30 when I tried the 75 hz, but I guess it will just be another computer mystery. :o

I have been using my G70 for over a year already 1440 x 864 @75HZ (Pal) with no issues at all :)

I have been using my G70 for over a year already 1440 x 864 @75HZ (Pal) with no issues at all :)

Well, it's obvious the projector is capable of the higher resolution!

Since my picture quality looks good, and I'm planning on getting a DVI input card soon, I guess I'll leave well enough alone for now.

Thanks for the note. :)

I have no trouble running higher resolutions on my G70, but I like 1280 x 720p @ 72Hz best for SD DVDs. Some people think otherwise, but I don't think there's anything to be gained by going higher.

You should be able to run 1080i @ 60Hz for HDTV and HD-DVD.

I have no trouble running higher resolutions on my G70, but I like 1280 x 720p @ 72Hz best for SD DVDs. Some people think otherwise, but I don't think there's anything to be gained by going higher.

You should be able to run 1080i @ 60Hz for HDTV and HD-DVD.

In fact, I do already run 1080i @ 60 hz from my Dishnet HD DVR (622). The picture looks outstanding. I currently use component video for that input, while my HTPC is into input B through RGBHV.

We almost have identical setups. I have a G70, Dish 942 and HTPC.

We almost have identical setups. I have a G70, Dish 942 and HTPC.

But you have John's DVI input card and are running all digital? How do you compare digital to analog?

I think you said you are considering HD-DVD as well?

I know the Toshiba HD-A2 and XA2 have analog output, but from what I understand the upscaling of standard DVDs requires the digital output, otherwise it's limited to 480p. That's why I'm interested in the DVI card.

I keep hearing how great the HD-XA2 is for upscaling standard DVDs, so I'm hoping the price will come down a bit.

But you have John's DVI input card and are running all digital? How do you compare digital to analog?. Nope. Again the same as you. I'm running HD component for my DVR and RGBHV for my HTPC.

I have a John's DVI card which I plug into the B slot (I pull the IFB-12 out) when I want to use my HD-A1, which is rare.

I should try hooking up my other gear to the DVI card, and will once I get the time. The sole reason I bought it was so I could hook use my HD-A1.

Our systems are so similar it's scary. :eek:

Nope. Again the same as you. I'm running HD component for my DVR and RGBHV for my HTPC.

I have a John's DVI card which I plug into the B slot (I pull the IFB-12 out) when I want to use my HD-A1, which is rare.

I should try hooking up my other gear to the DVI card, and will once I get the time. The sole reason I bought it was so I could hook use my HD-A1.

Our systems are so similar it's scary. :eek:

That's got to be a PIA to have to pull out the input card and replace it just to watch HD DVD!

I was going to buy an analog switcher so I could run the HD DVD via analog into the same input card. But then I read about the great upscaling ability of the new HD-XA2 player, and the only way to enjoy that is with a digital connection.

That's got to be a PIA to have to pull out the input card and replace it just to watch HD DVD!It would be, but I rarely use my HD-A1. I haven't used it in 3 or 4 months. I like to rent and rip SD DVDs to hard drives. I use my HTPC like a DVR. Ripping it allows me to watch the DVD when it's convenient. I usually delete a movie after I've watched it. The motive for all of this trouble is monetary. I get about 26 movies a month for $20. Can you say cheap bastard? :D

I think this summer I'm going to up my drive space from 1TB to 4TB and upgrade my HTPC to play and rip HD-DVDs. I will no longer need my HD-A1 at that point and will hook my HTPC up via my DVI card.

I got The Departed on HD DVD and my HD-A1 is getting a work out with that. :)

I have no trouble running higher resolutions on my G70, but I like 1280 x 720p @ 72Hz best for SD DVDs. Some people think otherwise, but I don't think there's anything to be gained by going higher.

You should be able to run 1080i @ 60Hz for HDTV and HD-DVD.

This mirrors my setup almost exactly. I have a VP30, so no frame-rate conversion for HD:

SD film to 720p/72
SD video to 720p/60
All 720p and 1080i HD "passed through" at their native rates.