Astound → [Speed] 10 Mbps in the morning, 1 Mbps at night in Somerville, M

I just got Mach 10 after tiring of Verizon. When I first installed everything, I was happy! Speedtest said 10 mbs, all was good. Then I noticed that after the sun goes down and everyone comes home, my speed TANKS. Right now I just ran speedtest and got:

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File size transferred : 14.75 MB (15468724 bytes)
Total time taken : 102.51 seconds (102512 milliseconds)
Throughput : 150.0 KB/sec [Kilobyte-per-second]
= 0.15 MB/sec [Megabyte-per-second]
= 1200.0 Kbps [Kilobit-per-second]
= 1.2 Mbps [Megabit-per-second]

Even my crappy DSL was better than 1.2 Mbps. Results are similar whether I go through my wireless router or direct connect to the cable modem. My modem's MAC is 00:12:25:86:eb:b6, for any friendly RCN techs that might be so inclined as to take a look. Is this just the consequence of sharing connections, or is there more I can do? Considering that during the day I can get 10 Mbps easily, I think my setup is fine and it's a local traffic issue.

You'll probably get more of a response if u sign up (only need a free account) - that way you can be PM'ed. RCN certainly isn't oversubscribed in this area - I get my full 20/2 every hour of the day.
You're absolutely sure there isn't something choking your upstream (e.g. a hidden trojan) ?
Best way to see the real throughput on the modem is with Toshiba Advanced Diagnostics (it works on a motorola cable modem) - but it doesn't appear to be on Toshiba's site anymore.

Since you've reposted here:

»[Speed] 1 Mbps d/l on 10 Mbps service

We'll close this one up.

Welcome to the site & the RCN forum, Kitesh.