Can't get dual channel RAM working

Skoopz

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Jan 6, 2014
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18,510
Hi guys, having a problem with my new build, I placed my ram how the manual says to have dual channel (basically putting the ram in the matching colour slots, grey or black) but no matter which of the two configurations I placed the ram it would boot loop without posting.
The build in question: https://uk.pcpartpicker.com/list/2fFV7W (ignore the PSU incompatibility it fits with a small amount of wiggle room left)

Incase it was faulty ram I tried each stick individually in each of the 4 slots to see what works, the system will only post if both sticks are in the very last two slots of the motherboard (the two far right slots) or if one stick is in either of those two slots. So I can only use the full 8gb (2 x 4gb) if both sticks are in single channel.

Now I'm at a loss, does this mean I have two faulty ram slots? (The two slots nearest to the processor)
It's not the ram because I can use both sticks in single channel and it shows as me having 8gb in Windows.
Tomorrow I'm going to try updating the BIOS and installing motherboard drivers; loosening the cooler a touch (read on other questions on here that can affect the Memory Controller) and reseating the CPU whilst checking for bent pins.

Is there anything else I can do? Really gutted that I pulled the trigger on a system upgrade just to have to RMA the motherboard potentially.