Intel Alder Lake compatibility questions

[happy user]

Hi! I'm looking for information about current compatibility status of the Intel Alder Lake platform (12th Gen).
By using the search, I was able to understand that in general the processor works with Proxmox. And that iGPU can not be passthrough in the Windows OS. But I also have deeper questions that I could not find an answer to:
Are all the cores recognized in the system?
Is it possible to understand which cores is P and which is E cores?
Can I appoint only E cores for some virtual machines?
Can I mix E cores and P cores for one virtual machine?
In fact, I plan an upgrade and try to understand whether it is worth choosing 12th Gen Intel or it is better to choose a Ryzen platform. I think Intel is more interesting, but I'm worried about compatibility with Proxmox.
Thanks.

 

[okiedokie]

Hi there, did you ever get answers to your questions?
I am planning a Proxmox build, but Alder/Raptorlake's big little architecture is concerning me
Maybe Ryzen 7000 is a better option, but I'm not sure how good the GPU suppport will be.

 

[leesteken]

Maybe Ryzen 7000 is a better option, but I'm not sure how good the GPU suppport will be.

I think this post might interest you. AM4 is very stable and supported now, but "obsolete" since a few days.

 

[okiedokie]

I think this post might interest you. AM4 is very stable and supported now, but "obsolete" since a few days.

AM4 isn't obsolute. But it doesn't include a GPU.

 

[happy user]

Hi there, did you ever get answers to your questions?

Hi. Nope. I still don't find any answers.

I am thinking about buying a 12th gen Intel first for testing and sell, if there are problems with compatibility. Because of this, I will lose in money when selling. So maybe I will just buy a Ryzen and that's it.

 

[_gabriel]

btw, E cores can be disabled in bios if you have issues about weird/wrong core allocation performance.

 

[Joe Piler]

Hi. Nope. I still don't find any answers.

I am thinking about buying a 12th gen Intel first for testing and sell, if there are problems with compatibility. Because of this, I will lose in money when selling. So maybe I will just buy a Ryzen and that's it.

Hello,

Checking in, I wonder if you ever found out about this? I'm currently trying to decide between ryzen 7000 and Intel 13th gen.

 

[harry4516]

I just installed Proxmox on a ASrock i5-1240p.
It works but was quite difficult.
The first problem is, that the current kernel 15.5 does not support the alder lake GPU, so no picture at all.
This was solved by editing the grub settings ('e' pressed in boot menu) and added nomodeset to deactivate the drivers.
Now it was possible to install proxmox, after installation I upgraded the kernel to 15.9 which supports 12th Gen GPUs.

I tested the performance inside a VM with all cores ON and also with only P cores ON and E cores switched off.It worked fine with all cores ON. So switching the E cores off did not give any advantage.

I was not able to iGPU passthrough to a VM, this make unknown PCI errors.

The speed measured inside a Linux Guest is excellent (sysbench) and almost the same speed as the basic system, so virtualisation works fine.

When moving a Window with the mouse (inside a VM) then the CPU load is quite high. Much higher ( 3 times) compared to my Proxmox on a i5 8th-Gen processor.
The reason is that the GVT-g feature is not more supported by the 12th gen CPUs, so all rendering is done by software, which makes is 3 times slower. There is a new feature SR-IOV which should be a good alternative, but since iGPU passthrough does not work, this also does not work.

My conclusion about 12th gen CPU for proxmox:
performance of P and E cores is excellent
GPU performance is bad, unusable for VMs needing fast graphics, we need to wait until proxmox supports SR-IOV with iGPU passthrough. But if it does in the future, it will run much faster than older CPUs using GVT-g.

 

[upagge]

@harry4516 Is it possible to determine which cores were assigned to the system? Can I independently specify which kernels to assign?

 

[harry4516]

I do not see any settings to assign the cores, from what I have read this is done automatically by the newest kernel versions (which are newer than the proxmox default kernel).

Regarding the bad GPU performance:
I tried to run my graphic programs in Ubuntu containers, since a container can access the GPU directly. And that work very well !
FreeCad and other CAD programs run perfectly smooth in the container, much better compared to a VM.
Now I can use the i5-1240p for proxmox

 

[das1996]

My conclusion about 12th gen CPU for proxmox:
performance of P and E cores is excellent
GPU performance is bad, unusable for VMs needing fast graphics, we need to wait until proxmox supports SR-IOV with iGPU passthrough. But if it does in the future, it will run much faster than older CPUs using GVT-g.

I wonder if the gpu passthrough issue is a function of the ASrock i5-1240p and would work correctly on a more traditional pc platform. Specifically, does the asrock have proper iommu groups?

I recall running the iommu script on a 12700k/z690 board some months back to see how it broke down the internal i/o. It had individual groups for all pertinent i/o (sata, network, video, etc.). What's the iommu groupings look like for the asrock? You can determine by running the script below

------------
#!/bin/bash
for d in $(find /sys/kernel/iommu_groups/ -type l | sort -n -k5 -t/); do
n=${d#*/iommu_groups/*}; n=${n%%/*}
printf 'IOMMU Group %s ' "$n"
lspci -nns "${d##*/}"
done;

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