Is this truly POST code E6 or is it Eb? It is easy to mistake the 'b' for a '6'. A 'b' looks like this:
POST Code E6 indicates a hang occurred while connecting a driver. POST Code Eb indicates that a hang occurred while executing a Legacy Option ROM. Since Option ROMs typically provide drivers to support associated add-in hardware or other capabilities, it is possible that either of these POST Codes could be seen if there is a compatibility issue with some piece of add-in hardware.
Seeing POST Code E6 can also be an indication that some particular portion of the processor or board (typically chipset) is failing initialization. This could be caused by bad RAM modules as well.
The typical compatibility issues being seen these days are related to the addition of a modern graphics card. For this, I have two suggestions,
Hope this helps,
First of all, if, by "The UEFI Bios...", you are referring to the graphical BIOS Setup capability, please do not confuse this with UEFI; they have absolutely nothing to do with each other. You could have a legacy BIOS that has a graphical BIOS Setup capability. Similarly, you could have a UEFI BIOS implementation that has a text-based BIOS Setup capability. That graphical BIOS Setup capabilities appeared on the scene at roughly the same time as UEFI is mostly coincidental.
Sorry for going off on a tangent here, but this is a major pet peeve of mine. This confusion was created by the marketing slime that worked for one of the motherboard manufacturers. They tried to assert that they were the first to ship a UEFI BIOS because they were the first to ship a graphical BIOS setup capability. In fact, neither of these claims was actually true. Intel had been shipping UEFI-compliant (Tiano Core) BIOSs for a number of years before this manufacturer ever did. Secondly, AMI had shipped a rudimentary graphical BIOS Setup capability in their BIOS core before this manufacturer shipped anything. Unfortunately, because of the sophistication of the Graphical BIOS Setup capability that they shipped (I have to give the scum that), the uneducated have fallen for these claims - and the confusion has reigned ever since.
Ok, off my soapbox.
Enabling UEFI support will, at least temporarily, require you to run without your graphics card installed. You will need to connect your (non-4K) monitor to the board itself. Immediately after pressing the power button to start the system powering on, start pressing the F2 key over and over until you see the BIOS Setup GUI (the Visual BIOS Setup program) appear onscreen. To enable, UEFI, click on Advanced and then Boot. Then, on the left-hand side of the Boot Priority scene, check the UEFI Boot option.
Hope this helps,
When you pulled everything out, you connected your monitor to the back of the board, right?
If you have everything disconnected - including Graphics card and all USB devices other than keyboard and mouse - then this leaves just the board, the processor and the memory that you have plugged in. Determining if the issue is in the processor requires testing in another system. Determining if the RAM is bad can also be done by testing in another system. Determining if the RAM is incompatible or the board is bad is something that we can do here. Follow these steps (note: add/remove DIMMs only with power off):
If you arrive at a point where it seems to work properly with at least one of the DIMMs, then replace the other DIMMs. If none of them work, then likely the board is bad and should be discarded.
Hope this helps,