Odd issue with ram and ASUS Sabertooth Z87

I have not tried ram in black slots only, but I will do that. I'll be upfront, I don't know how to memtest the ram. Do I need to download a program for this? Also, I'm pretty certain the BIOS is updated, but how would I check to make sure? I checked ASUS website, but there's like nine different BIOS update files: https://www.asus.com/Motherboards/SABERTOOTH_Z87/HelpDesk_Download/

Updated the BIOS with the latest version, switched the ram around so both were in the beige slots, and it works! Thanks a million. Will make sure to update BIOS next time.

Unfortunately my problem wasn't solved.

After updating the BIOS, the computer worked well. I shut it off. When I turned it on again the next morning, it exhibited the same behaviour it had in the past, where the computer was on but the BIOS wouldn't load up.

So I switched the ram slots around again, where they were both in the right black and tan slots. Computer works again.

Then I decided to try putting them both in the black slots. The problem was that my heatsink fan was in the way of the leftmost black memory slot. So I put the heatsink fan on the other side of the PC and put the ram in the leftmost black slot, and put the other stick in the right black slot. Boots up fine.

Then I get a brainstorm and put them both in the tan slots, and turn it on again. Success! It must have been that the proximity of the heatsink fan was screwing with them or something, right?

So now, two days later I'm watching a video and suddenly I get a blue screen of death with this message:

IRQL_NOT_LESS_OR_EQUAL

The computer shuts itself off, and then starts booting, shutting off, booting up, shutting off. I hold down the button to shut it off permanently, wait a bit and try to reboot it. It boots up, but it again refuses to go to BIOS. I'm back to square one. I put the two sticks in the two right black and tan slots, and it boots up fine again.

I've done some digging around and it sounds like the IRQL message is possibly a hardware issue? I'm at a bit of a loss here at this point. I don't know why it would refuse to work, then start working when i updated the bios, then seemingly arbitrarily stop working again, then start working when i move the heatsink fan around, and then arbitrarily stop working again. Never heard of anything like this. I'm going to be running memtest on the memory soon here, as I tried the other two options suggested and they don't seem to have been permanent fixes. I'm also going to list my hardware here, in case anyone sees anything that is glaringly incompatible:

Motherboard: ASUS TeK Sabertooth Z87 LGA 1150 Motherboard

Processor: CPU INTEL|CORE I7 4770K 3.5G 8M R

Ram: Kingston HyperX Beast (T3) - 16GB Kit (2x8GB)

Video Card(s): Asus GeForce GTX 770 Video Card (two of them, SLI)

Main Hard Drive: Crucial M500 CT960M500SSD1 2.5in 960GB SATA 6BPS 7MM Internal Solid State Drive

Secondary Hard Drive: 2TB Seagate SATA 64MB

Cooling: Enermax ETS-T40-TB

PSU: 750W Coolermaster GX 750-ACAA

Case: Thermaltake Level 10 GT Black E-ATX Modular Tower Case

I'm going to run the memtest this weekend. Until then, I'm really at a loss on this. Spent quite a bit of money on this computer, pretty disappointed that I'm having these issues with it.

I guess another question to ask is, what am I missing out on by not having the ram in the optimal configuration? I noticed that when I did get it to work in both tan slots, it booted up faster. Is there anything other than that? Am I actively harming any of the other parts by having them in a non-optimal configuration?