Please bear with me but before putting the ?'s which I hope owners will answer.... by way of background:-
I have read about and have had my own usb 3 (rear ports for me ) problems with Asus X99 boards. (my board is the S type). My first board was never right and replaced by Asus , my second was stable until I managed to bend a few cpu pins
and the third , recently received (new system , finally, fully operational 
), does appear to be stable.
(for me on all 3 builds stability seems to come by using as few usb 3 ports at the back of the board as possible and preferably using the rear usb 2 ports).
Apparently ,my new system, 'no problem' - all issues dealt with - I thought.
However a post by smsmasters in the past few days asking if I could see in Device Manager a driver for Asmedia USB 3 made me start looking and to realize that no such driver was installed . Strange?
Having looked at the 2 support discs (671.3 & 671.06 )I still own ,I know now why no such driver - and the situation does, to me, seem a little odd.
Again - bear with me.
When installing a new board I will , more or less immediately,after windows is installed , load the support disc and run 'set up' - in this case I consented to Asus set up running (on all 3 occasions).
Go to drivers and subject to just checking that I am not unintentionally installing some .... I will install.
Have checked both discs and neither lists an Asmedia usb 3 driver - so I did not install such ( just to mention I did install the Asmedia Sata 6 driver - which does appear to be functioning normally), BUT given the 8 (S board) usb 3 ports which the manual says are 'ASMedia USB3.00 controllers' the lack of a driver to install does seem 'strange'.
Checked Device Manager and the only USB drivers installed are Intel (the set up disc does list an Intel USB 3 driver- which I did install) or generic (microsoft/intel).
Decided to have a look at what was on the discs I have, but rather than run 'Asus Set Up' went - my computer/ asus disc/ open and found under drivers/usb3 a driver for Asmedia 104x usb3.
Also checked the Asus web site to find an updated driver for Asmedia for USB 3.1 / 3
Basic ?'s for users is 'have you installed the Asmedia USB 3 Driver' and if you did 'has it caused any problems or resolved any of such.'
Am wondering if the usb 3 problems flow from the fact that the Asmedia USB 3 driver is not installed?
and even if this is not the cause will the board function better (or worse) with it?
May be I have the total wrong end of this - my technical knowledge is , to put it mildly, limited . If I have messed up and the actual answer is simply down to my incompetence , my apologies , I am only trying to find out and , possibly, help
I have read about and have had my own usb 3 (rear ports for me ) problems with Asus X99 boards. (my board is the S type). My first board was never right and replaced by Asus , my second was stable until I managed to bend a few cpu pins
and the third , recently received (new system , finally, fully operational ), does appear to be stable. (for me on all 3 builds stability seems to come by using as few usb 3 ports at the back of the board as possible and preferably using the rear usb 2 ports).
Apparently ,my new system, 'no problem' - all issues dealt with - I thought.
However a post by smsmasters in the past few days asking if I could see in Device Manager a driver for Asmedia USB 3 made me start looking and to realize that no such driver was installed . Strange?
Having looked at the 2 support discs (671.3 & 671.06 )I still own ,I know now why no such driver - and the situation does, to me, seem a little odd.
Again - bear with me.
When installing a new board I will , more or less immediately,after windows is installed , load the support disc and run 'set up' - in this case I consented to Asus set up running (on all 3 occasions).
Go to drivers and subject to just checking that I am not unintentionally installing some .... I will install.
Have checked both discs and neither lists an Asmedia usb 3 driver - so I did not install such ( just to mention I did install the Asmedia Sata 6 driver - which does appear to be functioning normally), BUT given the 8 (S board) usb 3 ports which the manual says are 'ASMedia USB3.00 controllers' the lack of a driver to install does seem 'strange'.
Checked Device Manager and the only USB drivers installed are Intel (the set up disc does list an Intel USB 3 driver- which I did install) or generic (microsoft/intel).
Decided to have a look at what was on the discs I have, but rather than run 'Asus Set Up' went - my computer/ asus disc/ open and found under drivers/usb3 a driver for Asmedia 104x usb3.
Also checked the Asus web site to find an updated driver for Asmedia for USB 3.1 / 3
Basic ?'s for users is 'have you installed the Asmedia USB 3 Driver' and if you did 'has it caused any problems or resolved any of such.'
Am wondering if the usb 3 problems flow from the fact that the Asmedia USB 3 driver is not installed?
and even if this is not the cause will the board function better (or worse) with it?
May be I have the total wrong end of this - my technical knowledge is , to put it mildly, limited . If I have messed up and the actual answer is simply down to my incompetence , my apologies , I am only trying to find out and , possibly, help
