The P5K PRO I had until recently, had big fat (relative) solder bumps at the back side. On the up side, but, as said, also on the back(!) side. Well, on the upside it's no problem, you simply don't use screws with uneven structures on the underside of the screw head plus you simply don't turn the screws in tightly, but almost completely loose. Then those bumps will not come off.
But how about the back side? The brass stand-offs crush those bumps into pieces even from positioning and the necessity of pressing the board into that "Q-Shield" with tons of power. Let alone from screwing the board onto them. In ASUS systems, aren't maybe shorts caused by the crushed solder pieces the number one cause for hardware defects? Just wondering.
Now you could use those non-metallic washers that some people use. But how to know, if the board has or not has to be grounded with the underside of the mounting holes as well?? And does it have to be grounded with the upside of the mounting holes anyway?? Luckily the manual does not say anything about that . But you know even if you use those washers, you will never be sure if all backside solder bumps remained in a good condition because of the pressing of the board into that Q-Shield. Is it really normal by the way that you need to push the board into that "Q-Shield" with that much power to be finally above the brass stand-offs with the mounting-holes??? (Link to another thread started by me)
I simply can't imagine, what ASUSes imagination is about mounting that board without crushing the backside solder bumps. Solder is a relatively soft material. What were they thinking, when they designed solder BUMPS for the backside???? Show me just one motherboard that doesn't have (a) flat or (b) very hard solder that in addition extends widely over the contact area with the brass stand-offs.