Connectivity /throughput issues with Video/Audio conferencing and Multimedia Streaming.

I subscribed to Comcast Business as an at-home worker /consultant.

Primary to this is the need to conduct business via telepresence (e.g. WebEx, GoTo, Skype, if I'm lucky, "free" providers if I'm not) and to stream training presentations from providers like ITPro.TV.

My area recently had a prolonged outage (over 6 hours, with instability for an additional 4) and since that time, any of these services have been "spotty" at best.

Long initialization /connection times, timeouts, interrupted connections, etc.

Since I still had a few months on my old provider (DSL based), I switched back over to test.  Lo and behold!  Nary a single issue!

Speed testing to both 'speedtest.comcast.net' and 'testmy.net' show bandwidth within tolerance for my subscription (50/10).  Testing to providers speedtest sites is wildly random.  Anything from 2 Mbps down to 0 up, up to 12 Mbps down and 2-3 up.

Moving back to DSL, and near-line-speed results are achieved on testing with no issues observed during regular use.

Naturally, the modem has been cycled several times and testing has been both through my internal LAN setup (firewall to switch) and direct at the modem interfaces, with similar results.

Model: DPC3941B
Vendor: Cisco
Hardware Revision: 1.0
Serial Number: 289259000
Processor Speed: 447.28 MHz
DRAM: 1048576 MB
Flash: 128 MB

Downstream:

1.3-2.0 db
35-37 SNR

Upstream
34-37 db

Any further thoughts on troubleshooting, etc.?  More or better data needed?