You can try the latest Intel BIOS version 2053 released 8/18/2011. Make sure all the fan (front, aux and rear) should have all 4 pins to be correctly managed. Have you try run the front and the rear fan and see if they can run at different RPMs?
Now, in regards the G510 keyboard might be problem between hardware (board and keyboard). Hopefully can get fix with the new BIOS.
from what I hear regarding the new bios 2053 I will not try to update, because I have a MSI GTX560Ti.
The identical front and rear fans can be adjusted separately as intended. So, no issue here.
Right now the aux fan is directly connected to the power supply unit (12 V).
If I change the percentage speed of the rear fan in the Bios, the aux fan percentage speed will also be changed to the same value and vice versa. It does not matter if a fan is connected or not. I will verify this later (when I am home) but I am sure this will happen.
Maybe someone else here can check this as well. Just change the percentage speed value for your rear fan and then check if the aux fan value was also changed.
Regarding the keyboard I only wanted to mention this strange behaviour. I think (but I am absolutely no expert regarding programming) the USB ports or the Realtek soundship are initialized too late. I guess the Logitech keyboard is trying to verify the connection between the ports (either headphones or microphone) and the soundship. This takes maybe too long and the windows loading will start.
Thanks and regards,