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#1 Posted : Sunday, May 5, 2019 9:56:39 AM(UTC)

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Firstly an ASUS x99 i7 core 44-lane based system and secondly a 'vMix' reference Gigabyte x299 i7 core-x 44 lane system, both with a Decklink Quadro (4 x SDI input) and a Declink Duo (2 x SDI output). Audio is provided by a Focusrite USB2 scarlet 18/20i v2 audio interface. The issue I have affects both systems equally in the same way. In addition to my 4 x SDI camera inputs my preset also calls for 4 x NDI inputs. GPU's are GTX1070 8GB. Everything is running at 720p50 and all VT's / Stills are cut to 720p50 (1280 x 720).

When I load up my preset I experience one of two situations.

1. The preset loads, Render times are typically less than 13ms, but are always floating in an unstable fashion between 2 and 13ms. fps is pretty much showing a constant 50fps but may occasionally drop to 49 or creep up to 51. After several hours the render times start increasing u into the 60 and 70ms, and correspondingly frame rates drop as low as 33fps both equally unstable. The only way to resolve the issue is to reload the preset (either from the selector, or just hitting last). This does not always gurentee sucess, sometime we have to reload the preset 4 or 5 times before we get 'a good one' - but never fear we will be reloading it again in a few hours.

2. The preset loads and everything is already messed up withe render times and frame rates all over the place, and we just reload the preset again and again until we get a good one.

vMix CPU is typically 10% with total CPU usage around 45%, GPU is at about 43% both system and GPU RAM are bountiful and nowhere near limits (less than 50% of installed CPU/GPU memory used). I have used every diagnostic tool in the book. I see absolutely no difference in resources that I can reasonably monitor between when its running smoothly (albeit erratic on it's within parameter render times) and when the render times are so high the frame rates collapse, and the audio stutters.

Remember this is two separate systems, exactly the same issue. Any ideas?

All The Best

#2 Posted : Tuesday, May 7, 2019 3:17:09 AM(UTC)

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Both chipsets are known to have troubles with render times. X99 has it really bad, x299 should perform better, but still not ideal in my opinion.

I now stay away from workstation chipsets exactly for that reason. They are just not made for real time video, it seems. My newest builds are all based on gaming chipsets. Z390 with 9900k outperforms any workstation I ever built.

On x99 make sure you install the latest bios updates. Especially MSI has patched some issues in the past which could lead to high or unstable render times.

Since this is something which builds up, this could have to do something with graphics or movies which are loaded over time. You should check what builds up, and try to eliminate that.

Also: when you use an external output over a capture card, try to disable it. It sounds weird, but in all my builds, the external output is what makes the machine unstable. If it helps, try to not use a capture card, but an NDI output and a birddog to convert NDI to SDI or HDMI, it's a world of difference.

I have a x299 machine with lots of inputs (50+) running stable for a few months now, but it required some tricks:

I used triggers to load videos into playlists, and emptied them again once they are used with other triggers. An empty playlist doesn't seem to consume gpu bandwidth and memory. A movie which is loaded all the time does. the 10+ camera's are the only inputs which stay active all the time. All the movie content is loaded dynamically.

What is sure, is that although technically these chipsets should perform better than gaming hardware (more pcie lanes), in reality they don't when you really push it to the edge. I would choose a 9900k with 16 pcie lanes, with a PLX chip doubled to 32, 10000 times over an x299 with 44 lanes. It's just faster, more stable, and even cheaper.
#3 Posted : Wednesday, May 15, 2019 12:05:12 AM(UTC)

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Hi, I was taking similar problem with my system.
Solved problem when I fixed the size of Virtual Memory (Pagefile).

Reinaldo Martins
#4 Posted : Wednesday, May 15, 2019 12:50:25 AM(UTC)

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to what size you changed Pagefile?
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