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(Opinion) Should Windows 10 VM's be switched to Q35 by Default?

(Opinion) Should Windows 10 VM's be switched to Q35 by Default?  

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This is just an opinion question, that may eventually be moved to a feature request...  I personally have an Intel/nVidia GPU passthrough gaming VM...  When I purchased UnRaid originally, on my first VM attempt I used the i440FX machine type since UnRaid recommended it for all Windows machines...  A few months ago, when I was having other issues with my system, I decided to reinstall the VM and do some experiments on performance for my system...  The bottom line of that testing was the Q35 Machine type was noticeably faster, and more importantly it fixed several compatibility issues I was having with some of the games I was having issues with on the first VM attempt...  I believe that this is due to the i440FX not supporting PCIe devices, and even though it didn't affect bus speed, I think several of the games anti-cheat software or initialization code was looking for the PCIe bus and not finding it...  I have flipped all my VM's to use Q35 ever since, and have not had issues with that decision...


Bottom line, other than legacy OS's, is there still any reason to use the i440fx machine type?  And if not, is there any reason not to flip the default Windows VM templates or at least the Windows 10 template to use Q35 by default?

Edited by Warrentheo

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On 1/11/2019 at 9:11 PM, Warrentheo said:

I think several of the games anti-cheat software or initialization code was looking for the PCIe bus and not finding it... 

I haven't ran into any issues of this sort with PUBG, Battlefield V, or Rainbow Six Siege. All the games have been working great with GPU passthrough (EVGA GTX 1060 6G) in Windows 10 Pro with i440fx-3.0. Occasionally, BFV will crash or experience some stutter, but I believe that's a problem with the game and not the Unraid + VM setup.


PUBG uses BattlEye. And Ubisoft has ant-cheats to my knowledge. BFV...well the jury is still out on that one as EA/DICE uses FairFight which relies on server side statistical analysis, so...yeah.

Edited by Zer0Nin3r
Added machine type

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My results are showing that i440fx-3.0 is a little bit faster right now.


CPU: Intel Core i7-5820K Haswell-E 6-Core 3.3 GHz LGA 2011-v3 140W BX80648I75820K
CPU COOLER: Corsair Hydro Series H150i
MBD: ASRock X99 Extreme4 LGA 2011-v3
POWER: EVGA SuperNOVA 1000 PS 220-PS-1000-V1 80+ PLATINUM 1000W Power Supply
RAM: CORSAIR Vengeance LPX 32GB (2 x 16GB) 288-Pin DDR4 SDRAM 3000 (PC4 24000) (CMK32GX4M2B3000C15)
GRAPHICS: EVGA GeForce GTX 1060 SC Gaming (06G-P4-6163-KR)
CASE: Rosewill RSV-L4500 4U Rackmount Chassis
CACHE DRIVE: Samsung 860 EVO 500GB SSD
STORAGE: 9 x 3TB Hitachi 7200RPM


unRaid v6.6.6
Video set at 1080p
VM system drivers from virtio-win-0.1.160-1.iso.

The VM is hosted on the cache drive, along with the appdata and system directories. Cache drive is not used for anything else.

These tests were only run once. The graphics card is in PCIE slot 1. This slot is PCIE 3.0 and x16. It's the only graphics card in the server. I dumped the graphics card bios so i only need 1 graphics card in the server. Graphics drivers were current during the tests. There is also a LAN card in PCI slot 5.


How to passthrough an nvidia gpu as primary gpu in unRAID. (To dump your graphics card bios).


How to easily passthough a Nvidia GPU as primary without dumping your own vbios! in KVM unRAID


The server has 1 VM and 3 docker images. The VM has 8 CPU's (4 cores) pinned and 16GB of RAM. I also marked these same CPU's for isolation.


i440fx-3.0 (Upgraded Win10 ENT x64 1803 to 1809)


Cinebench R15 OpenGL: 87.95 FPS
Cinebench R15 CPU: 625cb

PassMark v9.0 rating: 3333.5

Nvidia System Information about Bus shows PCI Express x0

Star Wars Swam test on Steam (Scenario = Follow):  average FPS 54.75

3D Mark (Demo version on Steam) - Time Spy - Graphics score: 4264 24-27FPS
3D Mark (Demo version on Steam) - Time Spy - CPU score: 3263

q35-3.0 (Fresh install of Win10 ENT x64 1809)


Cinebench R15 OpenGL: 81.88 FPS
Cinebench R15 CPU: 624cb

Passmark v9.0: 3197.0

Nvidia System Information about Bus shows PCI Express x1


Still need to test these 3

Star Wars Swam test (Scenario follow) on Steam
3D Mark (Demo version) - Time Spy - Graphics score
3D Mark (Demo version) - Time Spy - CPU score

Edited by chris1259

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Something to mention I already posted in the qemu-pcie-root-port-patch feature request section. With i440fx 3Dmark on startup checks your system specs and let the VM freeze everytime. You can move the mouse and move your windows, but can't start or stop any programs or do anything in this situation. It will never fix itself. I had to quickly cancel the system information collector process in the taskmanager to get to 3Dmarks options to disable the autoscan to be able to use the software. Switching to Q35 and changing nothing else except for adding the Qemu bandwith options at the end of the xml the issue is fixed for me. Can someone test this maybe and report back?



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