8gb instead of 12gb

hi,dear.
i have a p6t deluxe v2,
the problem is , i am insterting 12gb ram but it recognize 8gb.
at first i have a dual channel with 2*4gb adata 1333 c4g9-r after that add 1*4gb adata 1333 c4g9-b .but it recognize just 8 gb on boot & windows.but software like speccy & cpu z recognize 12gb. i am changing the slot when using just the new one on a1 slot, bios recognize it for 4 gb.but when adding other that,bios donot recognize the new one.
my cpu is xeon x 5650.
i am removing the bios battery,reinserting cpu, and other test,but bios didnot recognize

When adding extra RAM it's critical that the new RAM has exactly the same timings as the old, otherwise they won't work together. I note that your existing RAM is adata 1333 c4g9-r and your new RAM is adata 1333 c4g9-b, now I don't know what the difference between these two suffix letters means but it does suggest that your new RAM is not the same as the existing and that could well be a problem.

ubuysa said:

When adding extra RAM it's critical that the new RAM has exactly the same timings as the old, otherwise they won't work together. I note that your existing RAM is adata 1333 c4g9-r and your new RAM is adata 1333 c4g9-b, now I don't know what the difference between these two suffix letters means but it does suggest that your new RAM is not the same as the existing and that could well be a problem.

Click to expand...

this socket had a problem.too many had this problem wih socket
you can see the timming are the same

Speccy runs as a Windows app which means Windows must be able to see all three RAM sticks...

ubuysa said:

Speccy runs as a Windows app which means Windows must be able to see all three RAM sticks...

Click to expand...

i found the solution.it is weird
i am inserting two old ram and it recognize just 4 gb.and one new and one old on a1 c1 it recognize 8gb ran.
slot b1 is ok,but in triple channel it doesnot recognize.before that two old are on a1 b1.
but when insterting on a1,a2,c1 . it recognize 12gb
thanks for your replying

Glad you're sorted.