USB tuner slow to respond

[johnsonx42]

I've noticed that my USB tuner is very slow to start. My USB HVR-850 (identified as an HVR-950 in the logs) seems to always take ~4 seconds to respond during the graph build process between the "Starting graph..." and "About to tune" lines in the log. In contrast, my PCIe HVR-1250 takes barely 100ms to start every time. The only time the HVR-850 starts quickly is if was in use for another recording and just stopped within the past few seconds.

Code:

2012-07-19 19:30:01.555    [INFO][13]    Creating BDA graph
2012-07-19 19:30:01.569    [DEBUG][13]    Using tuner WinTV HVR-950 BDA Tuner (1)
....
2012-07-19 19:30:01.630    [DEBUG][13]    Starting graph...
2012-07-19 19:30:05.355    [DEBUG][13]    About to tune BDA graph:

I immediately thought of windows power management, but the only device in the USB device chain that has a power management setting is the USB Root Hub device. I tried disabling power management there (the "Allow the computer to turn off this device to save power" checkbox), to no avail. The tuner itself has no such setting.

Anyone have any ideas?

@sub: is NPVR doing anything else between those two log lines, or is that the point at which you make a call and wait for windows to do it's thing?