I am trying to get a new PC up and running. Win 10, Asus X99 Deluxe II, i7-5930K, nVidia Strix GTX980 TI OC.

My (main) problem is that I get occasional spikes in render time. Lies around 0-1 ms, then (several times every minute) it goes up to 5, 15, even 40+ ms, and so on. And I sometimes get some stuttering in Preview and Output.

Yes, all drivers are up to date and I start from default settings with a new preset (1920x1080 50p). The spikes occur for example when I have a single Camera or just a Video input playing.

I think I've tried everything I can think of, except to use a different graphics card (will do that next week).

Unless - maybe one of you guys have an idea, or perhaps have noticed similar behavior and found a solution.

In any case, have a great weekend (I will - summer has hit Sweden).

Sounds like an interrupt conflict be the sounds of Maximus's post. I agree, shuffle the cards around in the available slots to see if it reduces this conflict.

http://www.helpwithpcs.c.../change-irq-settings.htm

Thanks for all comments and suggestions. I've tried moving around the cards, including the Nvidia, between slots. But that seems not to be the main problem.

After spending *many* hours on this problem I tried installing Asus GPU Tweak II. In it I noticed that the GPU clock spiked. Initially it starts at around 230, but on and off spiked up into the 800-1000 range. So, I installed GPU Tweak on another workhorse with a GTX970. That clock spinned steadily at 899. Maybe I was onto someting...

Back to the X99 machine and I selected "Always 3D clock" in GPU Tweak. Not sure what it does, except getting the clock to spin at a steady 1300 something. Now the render times looked normal. A little later, while experimenting with different things, I found that if I had three monitors attached to the X99/GTX980 (earlier I had only two) the clock spinned at 900 hundred something (without selecting "Always 3D clock"). The PC with the 970 also has three monitors attached, so that's probably why it's GPU clocked is always on 899.

As I added a Yuan SC542N4-SDI capture card (started with one Yuan SC542N4-HDMI), and attached a few cameras I noticed that 900 was not sufficient. But by using Always 3D clock it seems OK render time wise.

For the moment I am pretty conviced that there is an issue around how the GPU clock is controlled. For sure, I can setup my PC to always start GPU Tweak with Always 3D clock. But it would of course be nice to know why it sometimes seems to spin too low for vMix.

Still get a slight stuttering when Fullscreen is on, but not as bad as before (render time still sub 10 ms, and total CPU sub 30%). And I have yet to test with more capture cards, and their PCIe slot allocation. But that's another story...

Thanks Martin!
Changing to Maximum performance made no difference.

Instead I threw in a Magewell XI400DE-HDMI which seems to be working just fine in my limited test.
I think the Yuan SC542N4 should be X99 compatible, I'll check with them - but they behave strangely in this PC.

Also tried with an Intensity Pro, that one too have spikes on render times...

(off to The Big Apple for a week, so it while take some time before I can test further).

Hi Stefan, have you got a link to the 'yuan intranet server box' you mentioned in your last post?
Thanks
S

hi richard: check under the installed programs for the yuan software. i first uninstalled the old drive and installed the new and later found both yuan programs in the list of software. the i removed - un installed - the old software and this solved my issue.

reported this to yuan !

i also had an issue with the 4 input hdmi card which lost compatibility with my motherbord. but this seems to be fixed now.

I will try to include the manual and info leaflet of the stream box here an attachment. there is no info on the website of this nice little gem. saw it at ibc and then ordered one for testing and I really love this little thing. sdi hdmi dvi component input, only 2 seconds delay on my ipad over wifi. had to contact them again for the locator software that detects the box on the network.

but it really works and is easy to take along...

leaflet
manual

stefan

So I tried removing all drivers and video input cards. Then installing one SC542N4 HDMI again (in a different slot), installing its driver, but the render time spikes remain...

Sounds like your motherboard is limiting the speed of the pcie lanes.

I recently discovered a freeware program called hwinfo. It gives all info about every device on your pc, inclucing capture cards. It also tells you exactly what the maximum link speed is for every card in every slot. It's a good tool to debug issues like this one.

Just wanted to add that my previous post was premature. Turned out it was not stable at all. This week I tried again to update all drivers, Windows, etc. Still no good. So I spent a day throwing out the X99 with CPU and replaced it with a Z170 and a 6700K. So far so good (except that Yuan drivers are unsigned drivers, working on that issue - instead of celebrating New Year ;)

Anyways, the X99 Chipset issues has gotten it's own topic, so I consider this one to be closed.

This is an old topic but an issue we had with a recent top of the notch X299 build: Odd render time spikes that seemed to occur when external output was enabled, and especially when vMix was recording the output. These spikes coincided with crackles in audio that could specifically be heard on SDI output. There were also few but nonetheless skipped frames in the recorded material.

The issue seems to have gotten fixed by changing the refresh rate of the connected screen to match the frame rate of the production (in our case 60 Hz --> 50 Hz, production frame rate 1080i50). Now, after 30 minutes of testing, I have heard no more audio crackles and there are no skipped frames in the recording either. Render times spike at 17-18 ms, but mostly staying at 1-3 ms.