Zwift GPU VRAM use (and watching videos at the same time)

On long rides I often Zwift and watch TV/a movie at the same time (2 screens).
Previously this was never an issue but at some point in the last few months it’s started maxing out my GPU and I get jerkiness/screen issues on the movie (I don’t mind Zwift being a bit stuttery as I’m not really looking at that so much).
Looking with task manager I can see that the VRAM on my GPU (3Gb) has been filled and it’s starting to use system RAM, and “3D” and “Video Decode” are both up near 100%.
Interestingly if I start the movie before loading Zwift it’s sometimes OK for a while (I’m assuming it means that the movie player gets access to the faster VRAM and Zwift ends up partially in system RAM).
Machine is Pentium Gold G5400, 8Gb, NVidia 1060 3Gb, running Windows 10
I do have a 4Gb NVidia 970 in another machine I could potentially swap if it’s likely more VRAM might help.
It’s running “Ultra” profile at 1080, but reducing resolution to 576 in settings, or replacing the “Ultra” config with the “Basic” one doesn’t seem to help.

Does anyone have any other suggestions? I appreciate this may not be a RAM issue so grateful for any hints. Thanks!

Someone’s mentioned similar with the 3GB version of the GTX 1060 before. On my 6GB 1660 Zwift usually uses up to 4GB of VRAM (but no more) so if I had to guess I’d say the game doesn’t differentiate between the two versions of the 1060 and is maxing out your card. That said I’m unsure why it would be a recent thing, other than to say I believe they’ve been messing with the draw distance - intentionally or otherwise.

For reference the detail profile is set automatically, and you’ll get Ultra on the 970 too. Changing the resolution in game doesn’t normally help much because the primary bottleneck is CPU. The only difference is the 4K setting which does require a pretty big jump up in GPU performance to maintain the frame rate.

Sorry, I’ve no suggestions. But I’ve not had any problems that I’ve noticed. I do the same (normally YouTube, sometimes Netflix) quite often. Very similar settings to what you describe, although I’ve a worse graphics card (Gigabyte Nvidia GTX 1050 GDDR5 2GB PCI-E).

My CPU is 8 years old, judging by this comparison it’s a bit better than yours, but only slightly. Maybe the number of cores or architecture are what make the difference, I dunno. But if you have another CPU lying around that fits your motherboard, that might be worth trying.

His CPU is perfectly fine for Zwift. Cores/threads don’t make the slightest difference (I wish they did!), I can run it brilliantly on a 2c/2t G3258. :wink:

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Thanks. For anyone who finds this, my solution has been to use the “multi-GPU” feature in Windows 10:
Use BIOS menu to re-enable the integrated GPU
Install iGPU drivers
Connect one screen to the 1060, and the other to the motherboard video out
Works really well as the iGPU is running the movie and the 1060 is running Zwift - it’s now actually smoother than it ever used to be!
Only downside so far is that if I want to use the screens the other way round (for when I run, and want the movie on the other screen) it causes problems as Windows appears to switch everything onto the 1060. There’s a way to “lock” processes to certain GPUs but it doesn’t seem to work brilliantly as the screen is connected to the other GPU so they still have to talk to each other. I’ll keep experimenting.

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Good idea, nice one. :+1: