Dell XPS 8300 Bios config

I dont think the XPS series allows you to change settings on RAM like that.  General rule of thumb is to install matching pairs and to match those pairs with the ones already in the computer, example 1333Mhz DDR3 with the same.  Normally however if you install for example again, DDR3 1333 and have say DDR3 1066, the 1333 RAM will down clock to the slowest group of chips.  In terms of timings and so forth that generally is all automatically done by the BIOS and the memory chips itself so if you have DDR3 1333 in 2 groups of 2 with 2 different sets of timings the fastest one should down clock to the slowest one.

Have you run any diagnostics on the memory at all?

I dont think the XPS series allows you to change settings on RAM like that.  General rule of thumb is to install matching pairs and to match those pairs with the ones already in the computer, example 1333Mhz DDR3 with the same.  Normally however if you install for example again, DDR3 1333 and have say DDR3 1066, the 1333 RAM will down clock to the slowest group of chips.  In terms of timings and so forth that generally is all automatically done by the BIOS and the memory chips itself so if you have DDR3 1333 in 2 groups of 2 with 2 different sets of timings the fastest one should down clock to the slowest one. Have you run any diagnostics on the memory at all?

I know my motherboard/pc can run the new ram I installed because I used the crucial and kingston memory match feature on their websites. I also ran a memory diagnostic test in windows and the extensive testing feature that was in Dell Bios for my ram. All came back good. I might run the Memtest sometime later. My old ram is dd3 1333mhz, CL9 and 1.5 V and I have two of these. My new ram is dd3 1600mhz, CL11 and 1.5V and I have two of these. So in total I have two old ram and two new ram.

Hmm.. Then in theory the new ram CL and Mhz should down clock to the old values.  Maybe you can try just using the new ram for a few days and see if you experience the same effects.  It is possible however unlikely that the you have a bad stick.  I've slapped different sticks in with no problems as the computer just takes care of the clock speed.

Out of curiosity have you tried ram from different manufacturer's but same stats as well, and have you tried different ram with different clock speed, CL settings etc.? I heard that different ram from different manufacturer's could cause problems. But for me it's all the same brand. And are you using an Xps 8300? I'm thinking of changing out the two old ram sticks with two new ones and having all four dimm slots of the new ram. But I just don't want to spend another $60 just to find out the problem still exists. Originally I thought it could be bad ram but then it would've showed up somewhere on my tests. I've also read that some people who've had conflicts with ram with different CLs so that's why I'm leaning toward the buying new ram. I should also mention that originally I had the new ram in slots 2 and 4 but I kept getting errors more frequently like once every three hours. But then I changed the new ram to slots 1 and 3 and now I get them like once every 3-4 days.

RAM is generally all made the same as far as I know, its just quality of RAM and if your going Kingston and other major brands you shouldn't be having issues.  I spaced out if you have any issues on the original ram?  If not, I'd contact the company you got the ram from and ask for replacements.