Well it's the RAM.  The RAM however, is not bad.  It's just that I'm using two different revisions.  Four years ago I purchased 2x4GB of Corsair Vengeance.  A few weeks ago I decided I wanted 16GB total (XP10 x64 usage) - so I found my order history in newegg and bought the same stuff in 2x4 GB variety.  It may have been a coincidence or not, but while all four stick were working in harmony, yesterday they decided to quit.  

 

Booting with original sticks in slots 1 and 3 worked...  New sticks in 1 and 3 worked.  Each stick worked fine separately as 4GB.  But when I attempt to boot with all four (old ones slots 1 and 3, new 2 and 4) it won't POST.

 

Turns out the new sticks are a different revision (identical part number though)....  and my mobo doesn't like the differences....  hmmmm

Check the voltages 1+3 sticks are dialled in for versus sticks 2 and 4.

I can't even POST with all four... how would I set the voltage for four with only two?

here how to go about his

most fundamental test to do is to

remove all memory slots and power the PC on

at this point cross your fingers and hope for a beep sound

don't expect anything else other then a warning beeping sound

if you didn't get the warning beep; your board is fried

if you got it; then you can move on to the next test

 

restore your memory back in place

make sure all your peripheral equipment are disconnected (usb etc); pull all you pci slots out and re-seat them

make sure your pc is free of dust (use a new thin painters brush to clean tight places)

(do not connect peripheral equipment back in yet)

try to boot; still no go at this point?

 

from my experience, id go to the next thing i know 9 out of 10 is the cause

if when you turn on the pc; the power light comes on but nothing happens

its the power unit went bad; they don't go bad by not turning on

in many cases there's a low voltage enough to power the led's

in rare cases enough to get you through post;

but once you pass post and try to power up; everything turns black

switch your power unit; even if its just for  testing borrow from another PC and try it on your current (its plug and play; you cant go wrong)

Not sure if you saw the post at the top of this page...it's the RAM is four slot configuration / different revisions causing the issue.

 

Also I don't hear beeps... there is no speaker on my mobo.  I also have no LCD on my board.

I can't even POST with all four... how would I set the voltage for four with only two?

I'd a feeling you'd misunderstand what I was trying to say. What I meant was check, physically if it says on RAM sticks 1+3, e.g. 1.3V/1.5V, and if it says, e.g.1.8V on sticks 2+4. Sometimes some motherboards will only accept RAM sticks that are of a certain voltage rating and it is a good idea to have all four sticks at the same voltage rating, like I have in screenshot

They're all 1.5v

 

Both sets of two are this product:

http://www.newegg.com/Product/Product.aspx?Item=N82E16820233142

 

Just the newer set I bought a few weeks ago has a different revision number.

Same Make of RAM as me, if not the same speed, so is a very reliable brand.

 

If it is still new, perhaps you can get Newegg to change it for you and then test the newer sticks.

 

One other thing, I'd do. As your mobo sounds like it is has a Dual Channel RAM controller, even though you stated that each stick in a memory slot worked fine, i.e showed up as 4Gb each. and sticks 1 & 3 worked fine in memory slots 1+ 3 respectively, thus giving you one set of Dual Channel memory management, have you tried those newer sticks in slots 1+3 just to disprove that memory slots 2+4 are okay? If they do not  boot in that Dual Channel mode in slots 1+3, then you know that slots 2+4 are faulty. Has happened to me on an Asus board.

Yeah I did try that - both sets in 1/3

Yeah I did try that - both sets in 1/3

And when you fit sticks 2 + 4 in memory slots 2 & 4 does it boot? If not, then it is the memory controller for that set of Dual Channel memory management that is kaput, cos you have just proved both sets of 2x4 +2x4 working in memory slots 1/3.

I didn't try that... didnt know you could use just 2 / 4

 

EDIT:  Just tried that...  boots fine with both ram pairs.

 

How odd....

So, it is NOT the RAM, after all. This is a head-scratcher for sure.

You're telling me.

 

I can't prove it but I'd theorize my son creating static behind the case did something hehe.

A bus or supply loading issue with both banks of ram? A timing issue with both? How tight is the ram timing set in your bios? ... just tossing out some ideas.

Timing is set per X.M.P. "profile1" in BIOS.  I've always set it that way and like I said, initially, both sets of RAM were working fine.  Both were at 1866mhz, 2T, 9-10-9-27