New RAM, now it wont boot

[comando2929]

My computer has been running fine with its 6GB of RAM, but i decided to increase the RAM by 12GB to 18GB. I purchased some new RAM with identical specs to the current RAM, but when I put it on the Mobo i get POST codes 68 68 F3 over and over again and it it shows nothing on screen. Everything about the board is stock, no over clocking or updated BIOS or anything. I tried each new stick individualy with the current RAM(same result). Tried just one of the new sticks by its self (same result). Tried differnt slot arangements, 1,3,5,2 and 2,1,3,4 (same result). Computer still boots fine with the old 6GB of RAM, why wouldn't this new RAM work?

Full specs
:Mobo:
EVGA 121-BL-E756-TR LGA 1366 Intel X58 Micro ATX SLI Micro Intel Motherboard (newegg link)
:CPU:
Intel Core i7-920 Bloomfield 2.66GHz (newegg link)
:Old RAM:
G.SKILL 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (newegg link)
:PSU:
OCZ GameXStream OCZ700GXSSLI 700W ATX12V (newegg link)
:Main HD:
OCZ Agility 2 OCZSSD2-2AGTE60G 2.5" 60GB SATA II (newegg link)
:Main GPU:
EVGA 012-P3-1475-AR GeForce GTX 470 (newegg link)
:GPU 2:
EVGA 512-P3-N845-AR GeForce 8800GTS (newegg link)

:New RAM:
G.SKILL Ripjaws Series 12GB (3 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (newegg link) (RAM compare link)

[comando2929]

Update:

I now got it running with the new RAM only. I was sure I tried that configuration, but maybe not, or my video card wasn't seated right (My main graphics card sits in the way and needs to be removed to access the RAM clips and re-seated to test every configuration). Anyways, the computer runs fine with just the new 12GB installed (shows 12 usable). However the computer still won't boot when there is any combination of the new and old RAM?

Thoughts?

[GSKILL TECH]

Most likely incompatible chips.

Thank you
GSKILL TECH

[comando2929]

incompatible with what? the new RAM with the mobo, or the new RAM with the old RAM?

Why wouldn't the RAM all be compatable, its all the same timing and voltage?

[GSKILL TECH]

The new RAM and old RAM. Depending on the type of chips used, they can be incompatible. Since any configuration doesn't work, that appears to be the issue.

They are same timings and voltage, but dual and triple channel motherboards are very selective about this. Even same exact model memory can be incompatible. This is why we sell 8GB, 12GB, 16GB, 24GB, 48GB kits. The kits are matched and tested to work together. If this was unnecessary, we would sell individual modules and have you purchase as many as you need.

Thank you
GSKILL TECH

[comando2929]

So there is no way to get the two sets to work together?

Your saying that despite the fact that i have 3 unused RAM slots, i cannot add more RAM without scrapping all my current RAM and buying a whole new paired set?

Is this how all new RAM is or just gskill?

[GSKILL TECH]

If they are surely incompatible, then you can not get them to work together.

This applies to all RAM, but with G.Skill you can send all of them back to us, and we can test and send you modules that can work together.

Thank you
GSKILL TECH

[comando2929]

If I had bought the RAM at the same time would they work better together? Basicly, is it because The RAM was purchased so far apart that they don't quite work together any more?

[Tradesman]

It's possible to buy two sets at the same time and place and not be compatible, that's one reason the manufacturers sell 1,2,3,4,6,8,12 GB sets, they test then to ensure they will work together. You might pick up two separate sets and have one made with the last PCB of a lot and the other set have the first PCB from a new lot.....same with IC's. The differences could be infinitesimal but just enough that they won't play well together.

If you can post your BIOS settings I'll take a look to see if anything looks off, tRFC, CR, voltages could be off