Cat 5 is more than adequate to do gigabit for even huge houses. If some conductors aren't connected, have bad connections, or the order of wires is wrong, then

Cat 5 is more than adequate to do gigabit for even huge houses. If some conductors aren't connected, have bad connections, or the order of wires is wrong, then many gigabit ports will negotiate to 100 Mbps, which only requires four working wires out of the eight. A cable tester from Micro Center (if you're lucky enough to have one close enough to visit) is $7.99, plus a 9 volt battery (which, funnily, is about half the price of the cable tester). Amazon has the same testers for around $10. MoCA is great, particularly if you're using cable boxes that require Internet over MoCA and you want to replace the NAT router your ISP provides, but it's a bit silly to use MoCA when you have wires that probably just need to be re-terminated or terminated properly.