Does DDR3 have to be installed in Pairs?

[rwayne]

I have not built a PC for a while and am trying to get caught up on technology.

How does DDR3 work?

Does it have to be installed in Pairs? Or can it be installed in any number?

If a motherboard has 4 DIMM slots can it run off of 3 sticks of DDR3 assuming each stick is the same memory size?

 

[hunter315]

It works in any number, but installing it in pairs triggers dual channel mode which doubles your memory bandwidth.

 

[Guest]

Currently for consumer motherboards, Intel socket 1366 motherboards use tri-channel DDR3 controllers, while the rest use dual-channel memory controllers. On socket 1366 motherboards, you CAN install dual channel memory, but your memory performance is gonna take a major hit. Same goes for dual channel motherboards, if you install tri-channel memory, the performance is going to way lower than what's advertised. However, extreme overclockers sometimes use single DDR3 ram sticks or two memory sticks on a tri-channel motherboard to decrease bandwidth use and to avoid cold-boot issues. The "pros" of tri-channel memory is that a) you can have more moemory installed and b) the amount of memory bandwidth available is increased.

White papers on DDR3 can be found at JEDEC's website. JEDEC is a company that makes all the regulations and standards for memory and other components.

Hope this helped.

 

[Guest]

Whoops double post. sorry =D

 

[rwayne]

What about AM3 boards? Are there Dual and Tri-Channel AM3 boards?

So basically Dual Channel DDR3 ram goes in Pairs and Tri Channel goes in 3s

 

[hunter315]

There are no triple channel AM3 boards, only LGA 1366 i7s on the X58 chipset are triple channel, all AMD desktop systems are dual channel.

Like the names imply, dual channel kits come as twos and get installed as pairs, triple channel kits come as sets of three and get install as such.

 

[Guest]

Yeah, there no triple channel AMD motherboards, and yes dual channel DDR3 (and DDR2) goes in pairs and tri-channel DDR3 (no tri-channel DDR3) goes in 3s.

 

[rwayne]

It does not seem like tri-channel is really worth the price. When I look at Tri-Channel motherboards the price seems substantially higher then dual channel boards.

I think I rather get a dual channel mother board with 8GB of ram rather than a Tri-Channel with 6 GBs. It would likely be the same price if not cheaper.

 

[Guest]

Well, tri-channel motherboards (upper level Intels) have better CPUs, which accounts for the premiums. But the choice is yours.