I've just moved in to my new house on the 15th. Back in October I asked the vendors to do a speedtest before I made the offer on the house. They were with Telstra.
So why is Telstra so much faster? Should I swap my ISP to Telstra?
It might be that you are speed testing Optus at a busy time of the day.
If I was selling my house and someone wanted to know the internet speeds I would test it out of the busy times, perhaps early afternoon before the kids get home from school.
Edit. Should of added I presume you are on a 100mbps plan
Need more details. What plan are you on? What plan were the previous owners on? Im going to guess your on NBN. What type of NBN are each providing? Telstra will 9 times out of 10 be faster no matter what. Just how it is. Need to look whether pricing is worth the slower speed. TBH looks like your on a 25mbs plan and previous owners were on 100mbs plan.
Your other post about this same thing is already answered here:
You need to pay more to be moved up the NBN speed tier, they have 12/1, 25/5,50/20 & 100/40 etc