With 2.11.0 in windows7 I noticed usb based keyboard has intermittent key delay on either press or release.
Which (and how many) FPGA devices and what sort of computer CPU (netbook, low power, ?) do you have?
I suspect with ASIC that will get worse - i.e. whatever problem your computer has with the small amount of USB accesses at the moment, will only get worse as that increases with ASIC devices.
With ASIC, cgminer will be hitting the USB port a lot harder.
USB shouldn't have this problem with the low amount of USB access occurring at the moment.
Is it every 5 seconds? Is it every key? Or is it once in a blue moon?
Edit: also what is your USB layout - hubs, multiple motherboard ports, etc.
No fpga or asic devices, just 7970 gpu. MB asus p9x79 with mouse and keyboard connected to usb 2.0 via 4 port kvm, no other devices on any other usb.
It may happen once or twice within 5 seconds. This is very noticeable in content requiring constant user interaction, i.e. pc game. With 2.10.5 and kernels from 2.11.0 (renamed cl's to match 2.10.5) keyboard delay no longer occurs.