DDR3 dual channel v DDR2 dual channel

[DeathViperX]

I was curious about something. I noticed if you go AMD for CPU they won't support triple channel DDR3 yet only dual channel, for whatever reason.

Is the CPU incapable; CPU being the Phenom II, or is it just a price or business strategy AMD is doing atm until triple channel DDR3 is more "affordable?"

But if you have DDR3 say 1066 to be fair RAM and DDR2 both dual channel and DDR2 is also 1066 will the DDR3 outperform the DDR2 even though it's dual channel or not really given they're the same clocks?

[mjrhealth]

AMD p2 only support ddr3 on AM3 socket motherboards , when you use them in Am2 sockets they only support ddr2 ram. Thats it. Its a socket thing.

[DeathViperX]

Originally Posted by mjrhealth

AMD p2 only support ddr3 on AM3 socket motherboards , when you use them in Am2 sockets they only support ddr2 ram. Thats it. Its a socket thing.

Thanks but that much I knew already. Maybe I asked it confusingly. Hopefully this is more concise.

What I was trying to say was if you get the Nahalem or Bloomfield socket 1366 i7s they support tri-channel DDR3 which is supposed to be twice that of DDR2 but if you look at the Phenom II they only support dual channel DDR3.

My question was say you built a system with a Phenom II and used 1066MhZ DDR2 memory that is dual channel and same thing with DDR3 also in dual channel and both are clocked @ 1066MhZ will there be any difference being one is DDR2 the other the new DDR3 or not really since they have the same clocks?

Also what is the difference between dual channel and tri-channel memory if you have tri channel DDR3 @ 1600MhZ and dual channel DDR3 @ 1600MhZ how much, if any, of a performance difference is there?

[Psycho101]

If you run DDR2 and DDR3 at the same frequency with the same timings, they'll be completely identical in performance.

There's no triple channel on AMD PhenomII because the onboard RAM controler doesn't support it. Whether they could make a CPU that supports triple channel without altering the CPU socket design, I don't know. You'd certainly need a triple channel enabled board though, with the correct wiring and 3-6 DIMM slots.

The difference between the two is potentially a third. You may see close to a third more bandwidth using triple channel, but you certainly won't notice it in 99% of the programs and games out there. In heavily multi threaded apps maybe, but nothing mainstream really.

Intel dropped triple channel from socket 1156 CPU's as it was a great way to save costs without significantly impacting performance. For a general idea of how Dual/Triple channel effects things, look for some comparison reviews between 1156 i7 and 1366 i7.

Note that Bloomfield = socket 1366. Nehalem is the general architecture, which is also present on Lynnfield i5 and i7.