Originally Posted by Loren Pechtel
While it's possible that your ISP doesn't have a big enough upstream connection you shouldn't blame them for slowness in linking to distant sites. An ISP controls only two things--the speed of the connection between you and them and the capacity of the connection between them and the backbone. They are in no way responsible for any performance issues after the backbone is reached.
Since you get the 2500k off their speed test you know your uplink is ok. The only other thing they have any say over is their uplink. If that's too small you will find the speed varies by time of day. If that's not happening then they aren't at fault. Note that time of day variations can also reflect load on the server you are connecting to, don't blame them unless all sites show the same pattern.
I somewhat agree with you but sometimes the contention ratio comes into play and their connection to the backbone is the problem. If EVERYTHING off the WAN is slow except for sites local to the ISP then yes, you've got a 2' pipe connected to their 2" garden hose.
It would also help to know who the OP's ISP is here in the US and what package they're subscribed to. I have 1536Kbps upstream and see about 1200 of it from various sites.
Now, if it's ONLY the Slingbox that's slow, that's the latency issue. No way to correct that until you get home and install new firmware or have someone do it for you.