Ok...so dpclat.exe is a nice little program. This is my result:
At the extreme left (-33 => -30) is the latency BEFORE inserting the USB cable. At the extreme right (-5 => 0) is the latency AFTER removing it. This is extremely reproducible, and always results in a tenfold latency increase. Always experiencing dropouts, no matter what.
Have tried the following:
Different OSes (xp 32bit, xp 64bit, Vista 64, 7 64 (build 7068))
Different USB ports (including using a separate bracket with 2 ports from the mobo headers, thought it might be an IRQ problem)
Different computer (completely different hardware (ECS mobo, nvidia chipset)
Different card driver versions (when applicable)
Disabling non-used hardware (including network card)
Optimizing OS for audio (different tweaks, background processes, turning off services etc.)
Different output types (ASIO, ASIO4All, Kernel streaming, DS)
Imagine my surprise when lugging the card to a friends house and connecting it (nvidia chipset, amd processor, win xp 32)...works perfectly with no increase in latency when inserting the USB cable. No dropouts....it just works.
TASCAM US-144 USB soundcard
ASUS P5QL-E motherboard
Core2 Quad Q8200 processor
ATI 4650 graphics card
4 GB Kingston RAM
1 Samsung Spinpoint 320 GB 7200rpm
2 WD Caviar Black 640 GB 7200 rpm in RAID 0
Built in gigabit network card (Atheros)
Disabled internal sound codec
...but the latency is really nice when my card is not plugged in, at least...
Edited by midasen (26/04/09 10:48 PM)