Is there an FTP server you can run to? You can run an iPerf test to see your actual throughput and can isolate where the bottle neck is. Remember as a residential customer your speeds are best effort, not guarenteed.
Yeah, I own a server in a datacenter in Chicago. The bottleneck is the last mile here, and I guarantee it's not inside my house. I replaced all the cable in the house when we moved in, using RG-6 Quad. There's a single 4 way splitter (2 gig rated) to feed the three bedrooms and the living room. One of the bedrooms is converted to my office. When we bought the house it was a rat's nest of mismatched cable and splitters in the crawl space, and the cable at the entrance block had been weed whacked so many times the core was penetrated. Fortunately, Cox had left an extremely large drip loop, so I could cut the crap end off and crimp on a new one, using waterproof compression connectors and a new grounding block, this one (gasp) actually connected to a ground rod with proper sized wire. We went from "barely able to see shadows and some figures" on the screens to full 1080 HD that was crystal clear. It started getting crappy though after Verizon ran FIoS through the area, so I'm betting that they damaged an underground cable somewhere. Oh, and my contract is 50 Mb/s guaranteed, with "up to 100 Mb/s possible". Yeah, I'm not holding my breath on that, but I do intend to hold them to the terms of the contract.
Nice. Hold them to it. I know they will troubleshoot on the phone to cover their butts first. If they do dispatch a tech to test at the demarc, make sure to get their tested speed in writing.
Let's see, two years ago I got this: Now, on the same ISP, with same plan but a few miles away and in a neighborhood with a much higher density I got this: Less than half of the 25Mbps of bandwidth I'm paying for.