Borrowed laptop works, ours only does the optimistic ping

I borrowed a laptop that could read our FR5 identity immediately, then ours went back to occasional ping replies and service timeouts. Same bench cable, supposedly the same settings. Supposedly has been expensive so far. I'm arranging another comparison before the loan machine disappears. Which settings and observed results should we capture so IT gets something more useful than 'the other one worked'? This is the documented read-only check in our training cell