Quote Peter C:
My personal opinion is that in all cases the PCIe chipset designers simply implemented the PCI support so that it performed to the level that PCI was supposed to guarantee.
In fact soundcards depend on levels of performance from PCI that it did (usually) deliver, but never guaranteed. So any PCIe mobo that only supports PCI top the lefvel required of the PCI spec could have these problems.
I would agree with that that's a good guess Peter - musicians have always stretched PC technology in rather different directions from most other users, and particularly in the area of sustained PCI bandwidth.
The current PCIe solutions are primarily for those who want more graphic bandwidth for 3D work, and mainly irrelevant to musicians, who instead mostly need basic graphics but more sustained PCI/FireWire bandwidth.
So, it's perhaps not surprising that when push comes to shove, gamers are bowled over by the extra speed of their 3D virtual worlds, while we musicians find out the hard way that this is (initially at least) at the expense of the sustained PCI bandwidth we need to run audio interfaces and audio DSP cards.