[SOLVED] q35 vs i440fx

[oah433]

Hi
I am trying to understand when should I choose the machine-type to "Q35 vs i440fx", I understand that Q35 supports PCIe so I can do GPU passthrough but what about the i440fx, is the Q35 is that superior why do we still have it?
For my setup where I have bunch of VMs running apache + MySQL on some and Nginx +MongoDB on the others which machine type should I use and does it really matter?
Thx

 

[dcsapak]

i'd say for "most" vms it does not really matter, since nearly all of the functionality of the chipset/platform is virtual anyway. if you need some features from a newer platform (like pcie) i'd choose q35, but
else there is not much reason to choose it over i440fx

 

[oah433]

that makes much sense. thx a ton

 

[M4XWELL]

In real practice, why are there 2 options?
to better understand if possible

because I usually use "Machine: q35" for vms where my Processor is : host" does that make sense?

 

[dcsapak]

In real practice, why are there 2 options?

as i said, e.g. sometimes a device passthrough needs to be passed through as 'pcie express' device which is only available on q35

because I usually use "Machine: q35" for vms where my Processor is : host" does that make sense?

for this the machine type should not make any difference

 

[LostOnTheLine]

for this the machine type should not make any difference

The question I have, that it seems like @M4XWELL & others concerned about as well, is "Is there any benefit to using i440fx over Q35?"

I'm aware most things will not care, & that certain ones will care if it's NOT Q35. But what cases will it be preferred to use i440fx?
Like does it use less resources? If so then it will be best to use it unless Q35 is needed. That kinda thing

 

[leesteken]

The question I have, that it seems like @M4XWELL & others concerned about as well, is "Is there any benefit to using i440fx over Q35?"

i44fx does not have a dummy sound card (which can confuse software but can never actually be used for audio).
q35 has a virtual PCI-Express bus (which some drivers require/expect,but you can almost always passthrough PCIe device over virtual PCI bus with the same speed).
It's mostly Windows that cares about these details. Linux VMs don't care and you can hide devices by binding to pci-stub.
There are probably more (little?) differences. Please share them if you noticed or actually used them.

 

[LostOnTheLine]

i44fx does not have a dummy sound card (which can confuse software but can never actually be used for audio).
q35 has a virtual PCI-Express bus (which some drivers require/expect,but you can almost always passthrough PCIe device over virtual PCI bus with the same speed).

So it sounds like it's pretty much always best to use Q35 in all circumstances except when there's an issue with the dummy sound card, & if you patch a virtual sound card to the VM that fixes that issue completely.

So at the moment it sounds like the conclusion is that there's no real benefit to using the i44fx.