I had the same trouble - OK with 512, the minute you upgrade, windows crashes! The ram was good quality and matched, didn't matter. The RAM worked fine on everyone elses computer!!!! 
In the end I gave up because it is now a spare, but, have you tried a BIOS update?  
I'm about to, when I get around to it, but, there are 5 computers in the house and environs, so I haven't been rushed......after a year.......
				
			 
			
		 
			
				
			
			
				“- He felt that his whole life was some kind of dream and he sometimes wondered whose it was and whether they were enjoying it.” 
			
			
		 
	
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