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A little teaser of what is to come :)


I have not been able to measure a latency difference, but there is a slight performance drop when using DXGI over NvFBC.

Resistor hack, there is no way to modify the GTX6xx series into Quadros without changing them (I am also the author of that hack over on EEVBlog :slight_smile: )


@gnif aahh, I thought your name is familiar, because of eevlog.

anyway, I have 680, and I use it as Quadro but with patched qemu, I spoof device id to qemu and load quadro rom, and it works.


Nice! Care to document this so that others can use this method to enable NvFBC support if they wish?


Thanks! The pastebin formatting is all screwed up though.


Yeah, raw is ok, will fix it, I am on mobile atm :slight_smile:


Perhaps on your device, but on mine and via wget it’s missing all it’s line endings.


Uhhhh, doesn’t vfio-pci come with these options by default? Any reason to use the patch? I currently using qemu 2.9 with vfio-pci.x-pci-sub-vendor-id and vfio-pci.x-pci-sub-device-id to manually assign my GPU subsystem ID, it works well.

vfio-pci.x-pci-vendor-id and vfio-pci.x-pci-device-id also exist, use qemu-system-x86_64 -device vfio-pci,help for a full list of vfio-pci options.


I fixed formatting:

qemu spoof id pach

qemu command line arguments

That patch Alex Williams wrote to test error code 43, year ago or so.


Do you spoof your gpu with that? Do you use geforce as quadro?

This patch I posted is atleast year old, so maybe there is something already in qemu to spoof it.


Yes I did. I think that patch is now merge to mainstream or something.

Edit: But I did this to passthrough my laptop dGPU as it doesn’t have subsystem ID after passthrough. Not to use geforce as quadro.

Anyway, check qemu-system-x86_64 -device vfio-pci,help and see if those options exist in your qemu sometime?


Oh hey, EEVBlog! FYI, I was the video editor for the Chronos 1.4 Kickstarter campaign for tesla500.


Nice! I cried when they sent one to be crushed in the hydraulic press on YouTube :(. I know it was faulty but still. It would be super handy to get one of those at some point for latency testing. Perhaps a bit overkill though.


I just checked, on my old qemu 2.1 it not available (only my patched stuff), but on 2.91 i have vfio-pci.x-pci-sub-device-id , vfio-pci.x-pci-sub-vendor-id=uint32

I will try without patch in couple of days and report back.


Not overkill at all when you can calculate to the exact millisecond how fast the refresh rate of monitors above 180hz is with their fall times. Currently Level1 just uses a GH5 at 180fps.

Level1 seriously needs a Chronos 1.4 for their monitor refresh testing. I know David personally.


Nice!, I do also, I do all his server admin for him, who are you on the forums over there?


I don’t go on EEVBlog forums. My name’s simply Jack.

BTW, here was me working on those videos… in fursuit:


Hah! Brillant!


Let’s see where this goes:


Even quickies with @wendell leaves me satisfied.


That was more like foreplay. I crave release (of the source man, get your mind out of the gutter)