You’ve got a speedy, modern PC and a fast internet connection – so why is it that you can’t watch streaming videos without regular dropouts and interruptions?

These kind of problems can be frustrating, and they’re certainly tricky to diagnose. But the free DPC Latency Checker could help point you in the right direction.

The program works by measuring the time your PC is spending in deferred procedure calls (DPCs), a mechanism used by drivers to tell the system that they need to process data right away. Normally this all works just fine, but if a poorly implemented driver spends too long in its own DPCs then the delay can cause problems – like video dropouts – elsewhere.

Don’t be put off by the technicalities, though, because DPC Latency Checker is extremely easy to use. All you have to do is run it, wait and watch as the program graphs your DPC latency over time.

It's sounds technical, but DPC Latency Checker is very easy to use - you're just watching a graph

If the graph bars stay consistently green then you don’t appear to have any DPC issues. To confirm this, though, try triggering activity on particular devices. Copy some large files across the network, via a wired or wireless connection. Print something, use a USB drive or other USB device, and leave DPC Latency Checker running as you work. If the bars stay green no matter what you do, it seems your dropouts aren’t related to DPCs and the program won’t be able to help.

If the graph bars include regular red spikes, though, this indicates a potential issue, in that at least one of your drivers is spending so much time on its own work that it could very easily cause problems elsewhere.

Which driver? Good question. If you’ve found that the issue only happens when there’s network activity, say, that should already be a major clue. But otherwise, the best you can do is try manually disabling non-essential devices in Device Manager while DPC Latency Checker runs in the background, until you find the red graph spikes disappear. (The author’s website explains more about the process, including some important safety concerns – be sure to read it.)

And once you’ve identified the device, updating the driver may help (and you could alternatively remove or replace the device, depending on what it is: it’s your call).

DPC Latency Checker won’t solve your streaming dropouts problem all on its own, then. The program can provide a lot of useful feedback, though: if this is currently an issue on your PC, go download a copy immediately, and find out what it can do for you.