You have mis matched ram and bad cmos battery. Banks are 3 dimms not 2. 6 slots x 4gig = 24 gig max. Mixing speed and rank and vendor and voltage is not supported. Must be low density 1.35V ram. [URL] Dell Nor Crucial support or guarantee that you wont have "problems" if you have ram outside of the supported configuration. Or mix ram from various vendors or speed or rank etc. Not supported is not supported.  That does not mean its not in your machine. This is also why crucial will NOT rma ram that was not purchased thru their ram configurator. Dell does not support 3rd party ram and does not support processors other than the one that came with the unit. This is why 8 GIG Kits are 2 X 4  DDR3 PC3-12800 • 9-9-9-24 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 512Meg x 64  Max supported DIMM Size is 4 gig and total max ram supported is 24 Gig.    
Hello! Whenever I turn on my Dell Precision T3500 I get these lines on the screen: Alert! Memory failure detected in DIMM2. Time-of-day not set - please run SETUP program. Invalid configuration information - please run SETUP program. Alert! Previous processor thermal failure Alert! System battery voltage is low. Alert! Non-optimal memory population detected. To maximize performance, populate DIMMs as specified in the service manual. The following are my device specifications: Processor - Intel Xeon CPU W3565 @ 3.20GHz Installed RAM - 12.0 GB (4.00 GB usable) (Note: I actually have only eight gigabytes of RAM and all of them were usable before this messages appeared. I have no idea how they suddenly became twelve.) System type - 64-bit operating system, x64-based processor. Any help would be greatly appreciated, but I am only a young 16-year-old student and I have humble experience with hardware so please do not use advanced concepts... Thanks
Dell Precision T3500 errors