Hi Martin,
I installed ArcaOS on a refurbished HP Probook 6570b I got back in May just for ArcaOS ($250US). It has a 3rd gen i5 processor, 8GB RAM, a 120GB SSD drive and came with Windows 10 installed. I set it up to have Win10 and ArcaOS boot using Airboot. The only issue installing was it did not detect my serial port, but easy to install manually. Everything that should work does (no WiFi, but installed card is one listed as supported by IWM if it is ever finished) except sound, which 'works' but is distorted and echos. PCI log attached.