USB audio

[hma]

I'm trying to run a professional USB 2.0 Audio Interface (RME Fireface UC) with the i7 model and tweak the performance of the ASIO driver under Win7pro.
While trying to find the culprit of unusually high DSP load (compared to the performance of the device on much weaker machines and compared to the MME drivers) I noticed that the ASIO performance of the interface is significantly worse on the rear USB 2.0 ports than on the front USB 2.0 (FACE module) ports or on the USB 3.0 ports. I haven't run longer tests yet, but the identical setting seems to cause about 3 times higher DSP load on the rear USB2 ports.
Is there any setting in the BIOS that could cause this behaviour or is there even a BIOS manual?

Thanks,
Hendrik

[gabrielh]

The described USB2 rear port behavior may occur if you share the rear USB port with some USB low speed device. Please check if you don't have a mice/keyboard connected to the rear USB dual head port alongside with the USB audio device.