A 'WTF' Problem - Update BIOS, RAM Disappears?

[Matrices]

My MSI GD80 motherboard is paired with DDR 1600 Corsair XMS RAM.

On the 1.4 BIOS, all 4 GB is detected without issue.

I tried to update to the 1.6 BIOS because it fixes vDroop. However, BIOS now only shows 2 GB of RAM at POST, even though inside BIOS it says DIMM 1 and 3 slots are full. Windows tells me I have 4 GB of RAM but only 2GB is "usable". No explanation.

What the hell kind of bug is that?

The CPU is running at 20x190, with the RAM running at DDR 1520. I can't enter whatever number I like, it has to be a multiple of 5, 4, or 3. Setting XMP on or off does nothing.

If a stick of RAM was bad, I'd think that it would cause problems in the working 1.4 BIOS, but it hasn't.

 

[BillParrish]

I wanted to reply so you know you where not being ignored.

Frankly I have not figured up what is going on with the "ram goes away" deal.

Lots of posts with this problem with no good trend as to what the general issue it. Everything from a bad stick suddenly appearing, to heatsink too tight, to ram voltage settings, to random acts of Gods.

First step is to swap out the ram booting with only one stick at a time and see what happens. Memtest86+ boot disk and test if you dont find a bad stick and check you Vdimm.

Good luck.

 

[Matrices]

I think that, for whatever reason, there is just a "FSB hole" where all the RAM will not show up between certain values. At DDR 1560, all the RAM is recognized, but at DDR 1520, half of it is not. This is with the 1.6 BIOS. With the 1.8 BIOS, it seems like no value below DDR 1600 is recognized. With the 1.4 BIOS, everything is fine. Weird stuff, but obviously BIOS-related.