Dropped frames with Displayport but not with DVI

[katodevin]

Just finished up a brand new build with a G530 and a 7750.

Running FFDshow + MPC + MadVR. Resizing via FFDSHOW to 1.5x and pushing to MadVR

I'm seeing a TON of dropped frames (using the ctrl+J stat notes) when I'm connected to a monitor via Displayport (about 25% dropped). But when I'm connected via DVI, I see none. Really strange, I freaked out and thought it was my hardware, so I ordered a crazy beefy CPU on its way.

Any ideas? HDCP issues?

[Asmodian]

Interesting and sounds odd to me, I assume you are using the same display settings with both connections? i.e. 1920x1080 @ 60Hz. Which display is it?

[katodevin]

Interesting and sounds odd to me, I assume you are using the same display settings with both connections? i.e. 1920x1080 @ 60Hz. Which display is it?

Yep using same display settings, as well as the same DVI input on the monitor. Only thing that is changing is the output of the 7750 card, and the cable (verified to work with other computer/setup)

Display is my testbed Dell S2740L.

[iSunrise]

Yep using same display settings, as well as the same DVI input on the monitor. Only thing that is changing is the output of the 7750 card, and the cable (verified to work with other computer/setup)

Display is my testbed Dell S2740L.
For madVR to work correctly, it needs to detect your monitors EDID info and display refresh so it can display the video frames correctly and smoothly. Maybe madVR cannot detect that when you are connected over DP (Displayport) or you need to delete the old DVI EDID info, so madVR can detect it over DP correctly. Just ask madshi in the appropriate madVR thread. It´s also possible there´s a bug in madVR, because Displayport is very rarely used, even today.

[Asmodian]

Are you using an active or passive DP to DVI cable?

Displayport is not as "the same" as HDMI and DVI are. I am not sure what the differences are but I wouldn't use displayport without an active adapter or with a monitor with native DP (or as part of Apple's ecosystem). I swear I broke (colored lines present even after switching back to DVI) an old DVI monitor trying to drive it with a passive DP to DVI cable. I got a picture but I also got the colored lines. With one data point who knows, maybe the monitor just died right then, but....

Which video card does the system that works with the DP to DVI cable have? Did you test using the same monitor as well?

Does the CPU usage change when you are using DP vs DVI? What happens if you remove ffdshow from your playback chain?

Maybe test with LAV as the splitter and decoder? Aero Glass on/off? MadVR in FSE mode?

Sorry, I don't have any solutions just a lot of questions. :o

An aside: Why are you resizing in ffdshow? I would expect extra resize steps to just damage the video.

[Asmodian]

For madVR to work correctly, it needs to detect your monitors EDID info and display refresh so it can display the video frames correctly and smoothly.

I don't think MadVR uses the EDID info for anything except setting up the entry in the device menu. People tuning custom refresh rates wouldn't like it if MadVR assumed they were whatever was written in the EDID. Of course MadVR could be detecting the refresh rate incorrectly when using displayport but I don't think it would be related to the EDID info.

[iSunrise]

I don't think MadVR uses the EDID info for anything except setting up the entry in the device menu. People tuning custom refresh rates wouldn't like it if MadVR assumed they were whatever was written in the EDID. Of course MadVR could be detecting the refresh rate incorrectly when using displayport but I don't think it would be related to the EDID info.
That´s not what I meant or said. These were only examples to what madVR does when detecting a monitor (or a different connection to the same monitor, which can give different data when they are read-out compared to DVI) and they are part of madVR´s monitor detection.

If madVR cannot detect the monitor correctly madVR won´t work correctly. madVR needs to know the correct refresh and the correct composition rate so that it´s algorithms for displaying the frames can work correctly.

If he reports dropped frames with madVR only when connected over DP, there is either something wrong with monitor detection (and thus misdetection of the refresh rate) or the drivers do something different behind madVR´s back if he connects the monitor with DP (which is also related to the monitor detection then).

Either way, he needs to report that to madshi in the madVR thread, like I said.