ASUS X99 memory subsystem teardown
We received our ASUS X99 a few weeks back and immediately set it up in our lab to take a look at the DDR4 memory bus. The first thing we all noticds was the fan on top of the processor. It is very quite. In fact it is the quietest fan I think any of us has ever seen inside of a computer. Onto the memory! We got a hold of a 2 rank DDR4 DIMM from a vendor and plugged it in on top of our DDR4 DIMM Interposer that is attached to our FS2800 DDR Detective® When we look at a memory bus we really look at it! The eyes on the Address/Command and Control bus looked great at 1867MT/s and since they did we cranked it up to 2400MT/s. So the DDR clock itself is 1.2GHz. All is well and we were not failing any of the memory tests we threw at it including Memtest86, Google StressApp and ThirdIO's Nemesis. We also used our U4154A logic Analyzer and our FS2510 Interposer to do eye scan and burst scan's on the DQ lines. They looked great and completely jived with what our friends at Keysight were seeing. BTW Keysight tool it up a notch and clocked their ASUS X99 at 3.125GT/s and was able to successfully capture the DQ data signals. See that announcement here. So at first blush it looks like the folks at ASUS get a passing grade on thier first DDR4 implementation.