PC reboots/doesn't start with more than 2 Sticks


So here is the deal..
I've got myself new MOBO, new PSU, new CPU, new RAMS.

MOBO : Asrock B75 Pro3-M
RAM sticks : Crucial 4GB, 240-pin DIMM, DDR3 PC3-12800

I bought 3 sticks of RAM just for testing, later planning to get all 4 installed since i've got Dual Channel RAM system.

My problem: All of the RAM sticks are working fine if i install them by One or Two. But if i install all 3 of them, PC won't start at all and reboots right away, no beeps from MOBO ( I don't think my MOBO has speaker as well, since i didn't see any cables to plug for it.. )

This is how it looks if i explained bad:

Slot 1. RAM
Slot 2. RAM
Slot 3. RAM
Slot 4. Empty´
= Won't boot

Slot 1. RAM
Slot 2. Empty
Slot 3. RAM
Slot 4. Empty
= Work's completely fine

Has anyone had similiar problems or know's what could cause it?

My guess at the moment is as follows, but im seeking your advice, maybe anyone know's exactly what could be wrong?:
1. MOBO doesn't like that exact type of RAM sticks
2. MOBO doesn't wantz 3 out of 4 RAM slots in use, make it 2 or 4 only
3. Get 4th Same RAM stick and try again
4. Buy 2 same type but Different from current RAM sticks and try installing all 4

Right now i'm kind of confused what to do. ( 8GB seems more than enough but at the same time i want as much as possible since it's pretty cheap anyway. )
5 answers Last reply
More about reboots doesn start sticks
  1. Your MOBO takes dual channel RAM, you will have to have both channels occupied for it to operate (1 and 3 are 1 "channel", 2 and 4 are the other "channel").

    So option 2 out of all your options is the correct one.
  2. Thank you,

    But shouldn't Dual Channel RAM support 3 out of 4 installed as well? Like One pair will work as Dual and the solo Stick will work as normal?

    I guess i'll try to get 4th stick of RAM and try
  3. No, it won't work with 3. It will work with 1 stick though, so 1, 2, or 4 sticks, and it is safest if they are all the same RAM and even better if purchased as a full set.
  4. Thanks alot, will order the 4th stick now :)
  5. hahaha... tacodisco THAT is VERY unique.
    Chugot9218 is spot on.
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