Question 1

hard drive compatible ?

Accepted Answer

Jorjon
Yes the Sabertooth 990FX R3.0 will run the Older Disk Drives just fine.  I have two running for storage or huge programs and software.  My OS Windows 10 is Installed on the Onboard M.2 Socket 3 512GB SSD Module and it is super stable and crazy fast.  Hope this helps.  Bryan

Question 2

what is the best memory to run on this board?

Accepted Answer

I have been using G.SKILL Trident X Series DDR3 2400 in both the Sabertooth 990FX R3.0 and R2.0 motherboards. I run the memory at 2133 only because ASUS tech support indicated that there may be problems at 2400 because of the AMD chipset. I've had no memory problems and no failures over the last several years.

Question 3

what type of hard drive will be compatible with this motherboard ?

Accepted Answer

I am running five (yes, 5) SATA-II HDDs in my tower. 1 SSD & 4 standard 7200 RPM drives. Your power supply will be a bigger concern than the motherboard.

Question 4

Is this a big upgrade compared to the M5A99FX Pro R2.0?

Accepted Answer

Yes : If you have more than 4 USB 3.0 devices
Yes : If you want onboard USB 3.1 devices 
Yes : If you want an onboard M.2 SSD.
No : If You have more than 5 Hard Drives or like to use eSata without an add-on card
I bought this board to use while troubleshooting with my Crosshair V Formula-Z and just decided to continue using it.
It seem's to be a sturdy board , was able to get it to run my FX-9590 without any problems , Though now I have it running a FX-8350 along with 32 Gb of Corsair Vengeance.
I do recommend getting the optional 40mm fan if you're planning to water cool.
In my honest opinion I'd wait till the ZEN Summit Ridge comes out unless you're having problems.

Question 5

W-PUMP header
I'm going to be running this in a double closed loop water cooling system, with both pumps having molex power connectors.  I can't see any benefit from trying to convert them to 4 pin PWM just to be able to show the pump speed in the OS.  Two questions... 
1. Is there any reason why it would be beneficial to run my water pumps through the motherboard vs. just running them off the molex connections from my PSU?
2.  Would there be any problem running fans from this header?  (I will have 13 fans running in this system and am trying to control everything I can from the OS so it's not all running at 100% all the time)

Accepted Answer

The water pump fan header can be used two different ways with a pump.  1) Would be with a PWM pump to control the speed and 2) would be to simply monitor the water pump speed (most have a 3 pin fan lead).

By default the Asus WPump header is not in a PWM mode.   You would have to change a setting in the bios to actually use it as PWM.   If I remember right unlike the other PWM headers it will default to a 100% speed setting.   Which you can then manually change in the bios, the same as all the other fan headers (so your pump (or fan) isn't running at 100%).

Question 6

The 40mm optional fan for cooling the VRM's - can it be 20mm thick, or has to be 10mm?

Accepted Answer

You can use a 7mm or a 10mm fan. The 20mm fan is too thick. I used the 10mm fan.

Question 7

does this work with the amd fx-9590?

Accepted Answer

Runs my FX-9590 like a dream Overclocked to 5.2Ghz with Turbo off , also runing 32 Gb Corsair Vengeance and an EVGA GTX 1080 FTW.

Question 8

Does this support coreboot?

Accepted Answer

yes

Question 9

I recently bought one of these boards and I seem to have lost the m.2 setscrew can anyone tell me what size screw it is or where to get a replacement screw?

Accepted Answer

You can contact asus customer support. Maybe they'll send you for free

Question 10

the mother board has the eight pin connector in the top left comer but the power supply cable that has the 24-pin connector and the 17- pin connector the other cable is a 10-pin connector the one that goes to the 8-pin. What do I do to combat this?

Accepted Answer

I believe you are over thinking the problem.  As long as you have a power supply that has both a 24 and an 8 pin connector you should be fine.  If not, I would consider getting a modular unit that does.

Questions & Answers