How can I read the bandwidth in use over the PCIe bus ?

Question

I'm working on a streaming media application that pushes a lot of data to the graphics card at startup. The CPU is doing very little at the point when the data is being pushed, it idles along at close to zero percent usage.

I'd like to monitor which machines struggle at pushing the initial data, and which ones can cope, in order that I can get to a minimum recommended spec for our customers hardware.

I've found that PCs with PCIe 1.1 x16 slots struggle with the initial data being pushed over the graphics card.

My development PC has a PCIe 2.0 x16 slot, and it has no problems with coping with the large amount of data being initially pushed to the graphics card.

I need numbers to prove (or disprove) my point.

What I'd like is to be able to determine:

Which slot type is the graphics card on? What is the speed of that slot? Gfx card name Gfx card driver version

But most importantly, the data flow over the PCIe slot - e.g. if I can show that the PCIe bus is being maxed out with data, I can point to that as the bottle neck.

I know that system memory speed is also a factor here, e.g. the data is being transferred from RAM, over the PCIe bus to the graphics card, so is there a way to determine the system memory speed also?

Finally, I write in unmanaged C++, so accessing .NET libraries is not an option.

Answer 1

Do you get errors pushing your massive amounts of data, or are you "simply" concerned with slow speed?

I doubt there's any easy way to monitor PCI-e bandwidth usage, if it's possible at all. But it should be possible to query the bus type the video adapter is connected to via WMI and/or SetupAPI - I have no personal experience or helpful links for either, sorry.