So that's why a 2 systems were getting crappy speeds. Yes, 2. It had been used only to split a single drop from another switch between two systems.
New drop, happy clients.
Some stuff here is museum material.
I've worked at places where we repurposed old CAT3 cables for network connecting printers, desk phones, environmental sensors, etc. Rare occasions where 10Mbps works just fine. Using that to connect a PC would suck.