# Cant hit 23.976 Hz with Nvidia GTS 450 and Panasonic AE4000U Projector



## LordX (Jan 12, 2012)

Hey guys - I joined the ae4000u club back in January - and love the picture quality

My quick system specs:
Panasonic ae4000u 1080p projector
Denon 2808 AVR
HTPC w/ Nvidia GTS 450 Video

I simply can not make the video card hit 23.976 when I try to customize it - and I have had it hooked up 2 different ways. The first was DVI to HDMI in the beginning, and now it is straight HDMI through the Denon AVR. Both ways have had the same issue.

When I set the Refresh rate on my Video card to 23Hz - I get 23.9777. When i go to CUSTOM Refresh, and try 23.976 - I get an error that it was not compatible with my display! So I have gone to 23.975 which actually gives me 23.9738 (or 23.974 rounded). So each of these options are about equidistant from 23.976 and I get roughly the same amount of dropped frames (around 6 per hour).

I know that this is not terrible - but I actually notice the lost frame every now and then, and it ruins my movie watching experience.

I have turned off the 'frame repeat' option on this projector - because I didn't like the 'soap opera' effect that it was having on the movies.

So - anyone else run into this issue with an Nvidia card? Is there a way to tweak it to 23.976 even with this error?

Also - if I simply can not get this video card to output at 23.976 - are there some options on the projector that can help me not notice the dropped frames so much? Does frame repeat look soap opera like if the refresh rate almost matches the movie?

Thanks for any insight!


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## LordX (Jan 12, 2012)

Ok, so apparently I am not going to get the video card any closer than what it is now.

So I guess I need to focus on if there is something that can be done on the projector end.

There are two options I see in the manual:
Frame creation (with 3 modes)
Frame response (with normal and fast options)

Which option could possibly help with my issue WITHOUT causing the 'soap opera' affect that I am trying to avoid?

Read more: Panasonic PT-AE4000 LCD HD Home Cinema Projector: Official Thread - Page 12 - Home Theater Forum and Systems - HomeTheaterShack.com


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## Peter Loeser (Aug 11, 2012)

LordX said:


> When I set the Refresh rate on my Video card to 23Hz - I get 23.9777.


Maybe this is a dumb question but does it have a 24hz option?


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## LordX (Jan 12, 2012)

It does - but the 24Hz option is dead on 24hz. Not 23.976.


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## Peter Loeser (Aug 11, 2012)

Interesting that the 24Hz setting is dead on but the 23Hz setting is not. Does the projector offer multiple refresh rate options?

The way I read your first post, you have not tried it without the Denon AVR in the chain... Is that correct? If so, can you video directly to the projector via DVI and HDMI to the AVR for audio?

Also, how are you determining the "actual" refresh rates compared to the options selected in your graphics card settings (23/24 Hz)?


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## LordX (Jan 12, 2012)

Yes it was hooked up direct to the projector with the dvi to hdmi cable - same issue.

MPC-HC has the CTRL-J function that shows actual refresh.


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## Ile (Nov 23, 2010)

LordX said:


> So - anyone else run into this issue with an Nvidia card? Is there a way to tweak it to 23.976 even with this error?


It's normal for Nvidia cards.
http://www.anandtech.com/show/4380/discrete-htpc-gpus-shootout/5

Could be hard to get it right. Some say that Reclock helps.
http://www.avforums.com/forums/home...proper-23-976hz-nvidia-card-possible-all.html

I chanced to Ati because of this issue and use Powerstrip to create custom timings. It works much better than Ati or Nvidia drivers. It's shame that Nvidia doesn't provide needed info for Powerstrip, so they can't get Powersrip to work with newer Nvidia cards.


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## LordX (Jan 12, 2012)

SOLVED: - I was able to hit 29.97591 by doing this!

"Unless you change the "Active space" of 1080 lines, you will be OK. You will change Vblank (the vertical blanking interval) instead.



Total lines (1125 default) = Active space (1080 default) + Vblank (45 default).



(Usually "line" is used instead of "pixel" for the vertical interval.) If Vblank is decreased (resp. increased), the "retrace" from the last line of a frame to the first line of the next frame occurs faster (resp. slower), that results in a longer (resp. shorter) refresh rate. BTW



vertical blanking interval = front porch + vertical sync pulse + back porch



For example, if I started with "23.976 Hz" refresh rate with the default total lines, I got 23.97750 Hz. This is too long. To shorten it, the number of the total lines has to be increased. With 1126, I got 23.97560 Hz, not bad.



Refresh rate: 23.976Hz


Total lines Actual refresh rate
1125 23.97750
1126 23.97560



Next I started with "23.975Hz" and got 23.97431 Hz. To increase it, I set the total lines to 1124 and I got 23.97610 Hz. This is better.



Refresh rate: 23.975Hz


Total lines Actual refresh rate
1125 23.97431
1124 23.97610



The result varies in each system. You need to try and find the best combination."


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