the basics:
- asrock z97 extreme board = intel z97 chipset.
slightly overclocked, bios optimzed (vt, spread spectrum off, and so on)
- 1x zotac gtx 640
- 2x evga titan superclocked
- 1 display connected to the _intel hd4600_ (using display port); means the nv cards don't drive displays!
- 1 lenovo lt1423p ext. usb touch display, using displaylink, connected to an usb 3 port, power connected to a 2.1 amps usb plug.
latest intel drivers installed, in particular latest intel usb3 drivers, nvidia 344.48 drivers.
displaylink 7.5.5 issues (these are from the lenovo driver page):
when _any_ usb device is connected or disconnected after windows did start (i mean to any usb port), _any_ still connected usb 3 device is immediately degraded to usb 2 speed. this can be "resolved" by deactivating the lenovo display throught the displaylink manager. once it is reactivated, any of the usb 3 device is degraded again.
displaylink 7.6 / 7.7 issues
now the usb 3 devices turn to usb 2 moments after windows login. disabling the lenovo turns them back to usb 3 speeds, enabling it again back to usb 2.
even more problematic: with 7.6 and 7.7 one of the installed nvidia gpus (the last one) is apparently turned off by the nvidia driver; reads error 43, but when trying to activate, one can see it is running for few moments, until the driver dumps it again ... this obviously has to do with nvidia, but does
not happen with 7.5.5. using older nv drivers doesn't help either (can't use them anyway, because of sw dev requirements).
i currently stick with 7.5.5, and whenever i need to connect a usb stick or sthg. the like, i need to restart in order to get my usb 3 backup disk working again with full speed... thanks for listening.