This thread aims to gather info on known working hardware. Particularly useful if you can post info on components that are still available to buy new, although things posted here will likely go out of date before pressing submit. Still, here goes:
I've just built a system based around MOTU interfaces, using the 424 pci-x card.
CPU: intel core i3-2120
Motherboard: gigabyte GA-H61M-S2PV rev2.0
Firmware: FD
Graphics: CPU internal
Ram is generic dual channel
OS: win XP sp3
All is running well, dpc latency checker reports peaks of about 400, mostly sits around 55.
The system is happy at 64 buffers and will support 72 channels across 6 mixers with eq and dynamics on every channel.
Happy recording with reaper to an external USB disk.
I've got this in a 1u case so needed to manage the fan speed more than the bios permits. The included windows config tool should not be used. It causes severe dpc latency each time it polls the hardware status.
I've successfully used speedfan to keep the CPU fan quiet while retaining temp control.