Multiple GPUs, CPU and how they are used on a system with Vegas?

Rednroll wrote on 1/17/2020, 2:23 PM

Dear Vegas Tech heads, I've been scratching my head for awhile and wanted to open the discussion with you smart folks and hopefully have a productive discussion in figuring some technical GPU questions I've had. In starting this discussion, I'ld appreciate if you're uncertain then to be upfront and just say you're uncertain but to the best of your knowledge, you "think" this is how it works. I'ld like us to avoid any arguments and just be able to discuss openly on how we think things work without any judgements of being right or wrong.

In the past I've built my own DAWs/NLEs starting with a motherboard and adding all the separate components where a Graphics card which contained a GPU with a certain amount of onboard memory always existed. Thus, there was always only one graphics card with a single...maybe multi-core GPU running. The main point is that there was a single device which was responsible for all the system graphics processing with a single graphics card s/w driver.

At this time in my life, I'm done building my own systems and prefer the simpler approach of purchasing a laptop and just making upgrades to it such as replacing/adding SSDs, expanding the amount of system RAM, and connecting external peripherals.

What I'm getting at is that I've got some background knowledge on building my own system and understanding what each component does. However, when setting up my laptop I've been very confused with the GPUs since all laptops are now built with a (SOC) System On a Chip architecture CPU which includes an onboard Intel HD Graphics GPU, and then often there is an additional Nvidia or AMD higher performance GPU added to the system. Typically the higher the performance of the additional GPU, the higher the price of the laptop. Reflecting back to the building of my own DAWs/NLEs this seems like installing 2 different Display adapters into the same system which is where my confusion starts.

When setting up my current laptop out of the box, I ran an initial benchmark test which showed my system was using the built-in Intel GPU instead of the higher performing Nvidia GPU. See results here: https://www.userbenchmark.com/UserRun/6722024

This got me realizing that I needed to go into some Windows 10 settings and adjust them so Windows was using the Nvidia GPU instead of the Intel. Within those test results it also shows a FAQ with a link "FAQ - How to force Optimus or Switchable discrete GPUs?", where I went through those steps to configure Windows to use the onboard Nvidia GPU instead of the Intel GPU. Adjusting these settings provided the correlating benchmark results showing the Nvidia GPU was now being used. https://www.userbenchmark.com/UserRun/6724816

However, what I have noticed is that I have 2 separate graphics control panels. One for Intel and the other for Nvidia. I had assumed that since I had windows now assigned to use the Nvidia GPU, that I would need to do all my setting adjustments using the Nvidia control panel software but that is not the case. What further confuses me is that I have a 3 display monitor setup, using the built-in laptop display and 2 separate external monitors. When I go into the Nvidia control panel or the Intel control panel, they show all my monitors are being driven by the Intel Grapics card which I'm also assuming means they are using the Intel GPU to draw whatever I see on my screens.

Additionally, another setting adjustment in Windows 10 I found where I can designate specific apps to use a specific GPU for graphics and 3D processing. Therefore, I chose to assign the Nvidia GPU to Vegas Pro.

However, then I go into Vegas, in the Vegas preference settings there is another setting adjustment selection for Video Previewing Acceleration where I can select either the Intel GPU, Nvidia GPU or "Off". I found with my particular system, the "Off" selection seems to have the best performance in regards to select-able video preview quality and overall Vegas performance.

Here are just some of my questions that I am very confused about.

1. If I select the "Off" position for GPU acceleration processing, what does that mean? Does it mean Vegas is using my CPU instead of my GPU for video processing?

2. If I put the Vegas preview window on one of my external monitors, is that preview window being drawn by my Nvidia GPU because I now have it set that way in Windows 10 or is it being drawn by the Intel GPU because that's what it shows in my Nvidia Control panel, that the external monitor display is connected to the Intel Graphics card? Or it being drawn by my CPU because I have the setting in Vegas turned to "off"?

3. Is the Intel GPU handling certain tasks and the Nvidia GPU handling other tasks, in manner that overall GPU is being shared between them such as would occur with a multi core CPU?

4. What the H-E double "L" is going on here with all these settings in Windows, Vegas, and the multiple Graphics card control panels in regards to multiple GPUs being present on a single PC system?

I'm totally confused by all this in being able to understand what is really happening to make any setting adjustments in Windows, Vegas, or the multiple GPU drivers and their associated control panels to make any sense of what is the setting is actually doing.

Please, try to enlighten me.

Comments

RogerS wrote on 1/17/2020, 10:56 PM

I think you need to mentally separate performing graphical calculations and sending a signal to the display. CPU and GPU can both do the former with different efficiencies but not the latter.

fr0sty wrote on 1/17/2020, 11:52 PM

1. Yes. You notice a speed bump possibly because your CPU is more powerful at that task than your GPU.

2. I think the more powerful GPU handles all the displays by default, perhaps you can enable the intel chip if the other fails, not sure.

3. Yes, Vegas can be configured to use the CPU and both GPUs all at once. For instance, the intel quicksync might handle decoding your video (if it turns out to be better at it than your main GPU, test that out), the main GPU might handle accelerating effects applied on your timeline, and the CPU does the rest. When you render, you'll have the option of choosing intel quicksync or AMD VCE/Nvidia NVENC in the magix AVC and HEVC render templates.

It doesn't matter what you do in windows settings as much as what you select in Vegas. For decoding, look under the file i/o tab and test which works best for you. Then test which gives you the best timeline acceleration.

Rednroll wrote on 1/18/2020, 7:19 AM

1. Yes. You notice a speed bump possibly because your CPU is more powerful at that task than your GPU.

2. I think the more powerful GPU handles all the displays by default, perhaps you can enable the intel chip if the other fails, not sure.

3. Yes, Vegas can be configured to use the CPU and both GPUs all at once. For instance, the intel quicksync might handle decoding your video (if it turns out to be better at it than your main GPU, test that out), the main GPU might handle accelerating effects applied on your timeline, and the CPU does the rest. When you render, you'll have the option of choosing intel quicksync or AMD VCE/Nvidia NVENC in the magix AVC and HEVC render templates.

It doesn't matter what you do in windows settings as much as what you select in Vegas. For decoding, look under the file i/o tab and test which works best for you. Then test which gives you the best timeline acceleration.

Thanks for the responses.

For #2, here's what seems really confusing to me. When I open up the Nvidia control panel and select "Set PhysX Configuration". It shows the image below. I have it set to the "Auto-select (recommended)" setting, but then it shows on the diagram that my displays are physically connected to the Intel UHD Graphics 620.

When I look at the selectable menu items it shows these options.

So then I say to myself....ok, I'll try changing it to the GeForce 940MX to see what happens, where I guess what I was expecting to see when I did that was that the diagram would show that my 3 displays were now physically connected to the GeForce 940MX but that's not what happens. It shows this instead which looks the same as the auto select setting.

Rednroll wrote on 1/18/2020, 7:43 AM

Then to confuse things even more, to be able to configure my display layout settings, I have to go into the Intel UHD Graphics Control Panel since they do not appear in the Nvidia control panel.

Rednroll wrote on 1/18/2020, 8:04 AM

Here's the way I'm currently summarizing of what is going on with my system. Let me know if this seems logical or makes sense. Being honest, I'm totally unsure.

1. My displays are ALWAYS "physically" connected to the Intel UHD Graphics "video card".

2. In the Windows settings, I'm able to choose if the system is either using the Intel or the Nvidia GPU for tasks that require a GPU. So while my displays are always physically connected to the Intel Graphical card, I can choose which GPU that card is using for processing tasks including the CPU.

3. In Vegas I'm able to select what handles the real-time processing for the video preview window by selecting either the Intel GPU, Nvidia GPU or the CPU(OFF setting) in the "GPU acceleration of video processing setting."

Howard-Vigorita wrote on 1/18/2020, 2:40 PM

My Dell laptop is similar and I've tested it extensively vp16 & 17. I get the best results in Vegas benchmarks by going into the Nvidia control panel (in the manage 3D setting screen) and setting the preferred processor to Intel. If you're a gamer you can set this by app but I'm not and I don't. Then I set Vegas to use Nvidia in video preferences but also enable use of QSV encoding and decoding which will use the Intel igpu. Since the laptop display is probably hard wired to the igpu, I assume it'll always use it for preview acceleration no matter what you set anything else for. I've never touched the PhysX settings.

I just tried the userbenchmark.com thing you posted for your laptop and it seems to like the Nvidia much better than the Intel... so I guess I surfboard with Vegas.

Nvidia: https://www.userbenchmark.com/UserRun/23831468

Intel: https://www.userbenchmark.com/UserRun/23830938

Rednroll wrote on 1/19/2020, 3:18 AM

My Dell laptop is similar and I've tested it extensively vp16 & 17. I get the best results in Vegas benchmarks by going into the Nvidia control panel (in the manage 3D setting screen) and setting the preferred processor to Intel. If you're a gamer you can set this by app but I'm not and I don't. Then I set Vegas to use Nvidia in video preferences but also enable use of QSV encoding and decoding which will use the Intel igpu. Since the laptop display is probably hard wired to the igpu, I assume it'll always use it for preview acceleration no matter what you set anything else for. I've never touched the PhysX settings.

I just tried the userbenchmark.com thing you posted for your laptop and it seems to like the Nvidia much better than the Intel... so I guess I surfboard with Vegas.

Nvidia: https://www.userbenchmark.com/UserRun/23831468

Intel: https://www.userbenchmark.com/UserRun/23830938

That's some interesting stuff there. I had been recently wondering, given the level of my poor performing GPUs if I should consider changing all my windows settings to use the igpu and set Vegas to use the Nvidia GPU, and that way it would seem that the Nvidia GPU would be dedicated to Vegas tasks and nothing else.

How are you able to isolate and perform Vegas benchmarks?

RogerS wrote on 1/19/2020, 6:15 AM

The load on Nvidia from just running Windows should be around 0 percent, so that's not your issue. Windows GPU setitng is for other applications, not the OS itself. If you do have other GPU using applications open I think that could limit Vegas performance.

j-v wrote on 1/19/2020, 6:57 AM

Everyone can check this on his/her own hardware by trying what you want and with your wished special settings of a program (f.i. Vegas) and look at the taskmanager's use of CPU and one or more GPU's while doing your thing.

To see differences in use of the settings in Vegas turn off one or the other GPU in the Windows Device Manager and look

fr0sty wrote on 1/19/2020, 2:08 PM

3. In Vegas I'm able to select what handles the real-time processing for the video preview window by selecting either the Intel GPU, Nvidia GPU or the CPU(OFF setting) in the "GPU acceleration of video processing setting."

Your video decode setting used in the file i/o tab of preferences also affects the speed of your real time preview, and you can have it set to use either GPU.

Howard-Vigorita wrote on 1/20/2020, 10:50 AM

How are you able to isolate and perform Vegas benchmarks?

Really can't isolate the gpus on my laptop. Mine has no bios setting to turn off the Intel igpu, I assume because the built in screen won't work without it. On my Asus system I can, however, so it provides a better basis if you're looking to draw inferences on cause and effect. A less reliable possibility is disabling the driver in Windows... but I've found that's not an absolute shut-off because the Windows default driver seems to use the hardware anyway. As do the Intel CPUs and chipsets which have a back-door interface to their iGPU. Best I can do on the laptop is try the various combos of settings in Vegas and the drivers and see what runs fastest. There's also the Windows Task Manager screens which graph the load being reported by the GPU drivers to Windows. I mostly focus on benchmark numbers here only because they're most easily duplicated and verified by others. For my own purposes, I also spot check using my own concert projects, which takes much longer as they tend to run in hours rather than benchmark minutes.