@rodluz Updating the kernel to the latest version helped; the computers are finally being restored at full and consistent speeds, for both unicast and multicast deployments. Thank you for your help.
I had a problem when capturing an image when the computer was in legacy mode, when it was in UEFI mode everything worked. Then I reinstalled FOG on PROXMOX and I didn’t check Legacy mode anymore, but now I just tested imaging in legacy mode and everything works. That’s why I thought it was somehow dependent on whether fog was installed in UEFI/Legacy mode. Topic to close then.
thank you george, the current switch is unmanaged, it’s a simple switch. There is not much in the specification of the switch, so I bet that switch is the problem.
All PCs are the same and support WOL and on the old switch they all turn on, but I will check it, maybe one of the students has changed something in the BIOS