I recently bought another 4gb of memory for my pc and since I already had 2*2 gb I bought another 2 sticks of 2 gb to fit the remaining 2 slots of my motherboard.
The motherboard is an ASRock X38 Turbotwins (so it is a few years old) but according to the specifications it supports up to 8 gb of memory in 4 memory slots.

The problem I see is that immediately following POST (which is successful with 8gb) either the pc just reboots itself or windows 7 reports an error (an unspecified BSOD) during the initial load before the windows logo and reboots the pc.
I tried with an Ubuntu live cd as well but it also failed to load.

I'm using Corsair XMS3 memory but due to an error the old and the new memory is not entirely the same (the old is XMS3 DHX, the new is not), but the specs are almost completely similar (same latencies and speed).
Old memory is here
New memory is here

The new memory and the old memory works fine by itself and both memory slots work as well but just not together.
I've made sure that the similar types of memory are in the correct dual channel slots (new with new and old with old).

My questions are:
1) Is it even possible to run with 8gb in a 4*2 configuration on this motherboard?
2) If yes, is it possible with the memory I have now or should I buy 2*2 more of the new kind to match the memory completely?
3) Do I have to change any settings in BIOS to get this to work?