Quick Dual Channel Question.......

Wiggins · 21 May 2008 at 20:40

I currently have 2gb Corsair XMS2 6400C4 (2x1Gb) and would like to know if I was to buy 2x512mb sticks of the Corsair XMS2 6400C4, would I still get Dual Channel?

Ta

lord filbuster · 21 May 2008 at 21:30

provided the 1GB sticks are in one bank, and the 512 sticks are in the other, yes. Should be colour coded, check your mobo manual.

Cob · 21 May 2008 at 21:40

1.5gb in one bank, and 1.5gb in the other and you should be fine.

lord filbuster · 21 May 2008 at 21:44

i don't think you can mix different sized ram modules in the sam bank and still run in dual channel.

Wiggins · 21 May 2008 at 22:11

Cob said:
1.5gb in one bank, and 1.5gb in the other and you should be fine.

I understand that the 2 types would have to go in the same color coded slot. My question is as they are different size modules, although they are the same manufacturer and speed/timings, will I still get dual channel?

lord filbuster · 21 May 2008 at 22:24

yes, if you have the 2 1-gig sticks as one pair, and the 512's as the other pair.

thegoonden · 21 May 2008 at 22:25

Yes, because each pair is operated separately.
The only thing is that they will all run at the speed of the slowest pair.

Cob · 21 May 2008 at 23:15

Dual-channel will only run if each set of slots has the same amount of RAM ie - 1.5gb in one colour, and 1.5gb in the other colour.

james.miller · 21 May 2008 at 23:17

Cob said:
Dual-channel will only run if each set of slots has the same amount of RAM ie - 1.5gb in one colour, and 1.5gb in the other colour.

could you prove this with bandwidth tests?

lord filbuster · 21 May 2008 at 23:38

not on an intel chipset. flex mode means you can just whack the same size modules in the same colour slots. Not sure about amd though.

james.miller · 21 May 2008 at 23:51

it cant be proved

dual channel is pretty simple and people do over-complicate it.

as long as both banks have memory, it'll be dual channel. the only caveat being if one channel has more than the other then whatever is left over will be accessed with single channel bandwidth (say, if one channel has 1.5gb and the other has 1.0gb).

there could be issues of a board refusing to work like that, but thats a difference issue. ive successfully run difference sized stick of ram in boards as far back as my abit nf7-s

Wiggins · 22 May 2008 at 08:28

james.miller said:
could you prove this with bandwidth tests?

So if I was to put 1x1Gb stick and 1x512mb stick in the red slots and the same into the yellow slots, it would then run in dual channel mode?

I thought that it would be the 2x1Gb sticks in the red slots and the 2x512mb sticks in the yellow slots.

Cob · 22 May 2008 at 10:15

james.miller said:
could you prove this with bandwidth tests?

If I could be bothered this morning I could probably show a 5-10% gain in memory bandwidth. But it's hardly worth the effort.

As has been said, there's no real noticable hit from running in single-channel or 'flex', but if you have the right combination of sticks to run in dual-channel then it's worth doing so.