[SOLVED] 3 Rams How to configure

[raptor7x9]

Helo i have 3 ram sticks 2 are of the same company cl9 ddr3 1600 and one is a cl11 ddr3 1600 different company when i install them my motherboard runs them in dual channel automatically but i wonder which rams should be in which slots for getting the best performance i have 4 slots 2 slots each for dual channel
How do i configure my memory do i put the same company memory in the dual channel slot and the other company memory in the other slot or do i put different company memory in dual channel slot

 

[Darkbreeze]

IF you are going to run a pair of DIMMs plus one oddball, then the two matched DIMMs should be in the second and fourth slots over from the motherboard, which for MOST motherboards will be labeled the A2 and B2 slots. Some boards will call them DDR3_1 and DDR3_2, but they will STILL be the second and fourth slots over, with the fourth slot being the one closest to the edge of the motherboard.

The oddball DIMM should be installed in the slot closest to the CPU. There are architectural reasons for this placement, and while other population methods might work, this is the method recommended by all manufacturers for consumer dual channel motherboards AND by JEDEC, the group that oversees the memory architecture specifications.

 

[raptor7x9]

IF you are going to run a pair of DIMMs plus one oddball, then the two matched DIMMs should be in the second and fourth slots over from the motherboard, which for MOST motherboards will be labeled the A2 and B2 slots. Some boards will call them DDR3_1 and DDR3_2, but they will STILL be the second and fourth slots over, with the fourth slot being the one closest to the edge of the motherboard.

The oddball DIMM should be installed in the slot closest to the CPU. There are architectural reasons for this placement, and while other population methods might work, this is the method recommended by all manufacturers for consumer dual channel motherboards AND by JEDEC, the group that oversees the memory architecture specifications.

Thank you veryy muchhh

 

[Darkbreeze]

👍

 

[SamirD]

Interesting...what's the reasons for this placement? I know the one closest to the cpu is usually the quickest/highest priority/whatever, but the other placements probably have reasons too.

 

[Darkbreeze]

Short version is this:

From the electrical engineering point of view, the DRAM dies provide adjustable bus termination and putting the only active DIMM for each channel on each channel's last slot puts them at the end of the bus where those bus terminations will be most effective at mitigating signal reflections, which should give you the likely best chance at trouble-free operation - the 5mm unterminated bus stub from an unpopulated DIMM slot before the bus termination is less disruptive than a 10-15mm stub at the end of the bus from the extra PCB trace distance and connector.

Support for multiple DIMMs per channel almost got scrapped from the DDR4 spec due to such signal integrity concerns.

-InvalidError

 

[SamirD]

Short version is this:

Thank you so much! Same issues back in the days on the SCSI bus before LVD and active terminators came around. Makes perfect sense. Plus, it also means that they can fix the problem in the same way with active termination on each of the sockets--probably something we'll see in DDR5 I'm guessing now that I know about this.