Inspiron 620 RAM Issues

I replaced the factory installed (2x1GB) RAM with a set of G.Skill DDR3-1333 2x4GB RAM (P/N F3-10666CL9-4GBXL). Ever since then I have been getting random BSODs and screen freezes.

My immediate reaction was I got some bad RAM; however, running Memtest shows no errors.  In addition, I removed one of the sticks (so there would only be 1x4GB of RAM installed) and no more BSODs or freezes. I tried this with each of the sticks and experience no problems which leads me to believe the RAM is just fine.

I've have the latest BIOS installed.  All my drivers are the latest.  I am not overclocking anything. 

Any thoughts as to what could be the problem?

System Info:

Inspiron 620
BIOS Version A04
Windows 7 Home Premium 64-Bit (Service Pack 1)
Intel Core i5-2320
Intel HD Graphics

 BSOD Info:

Bug Check String: PAGE_FAULT_IN_NONPAGED_AREA
Bug Check Code: 0x00000050 
Caused by Driver: ntoskrnl.exe 

(also have received the following as well)

Bug Check String: IRQL_NOT_LESS_OR_EQUAL
Bug Check Code: 0x0000000a 
Caused by Driver: ntoskrnl.exe