Single/dual Channel?

[Amarjit]

Which would surpass in efficiency: three DIMMs, 1536MB of DDR SDRAM, operating in single-channel or two DIMMs, 1024MB of DDR SDRAM, operating in dual-channel?

[clocker]

I think it would depend entirely on the motherboard.

[Snee]

I heard that the dual channel benefits aren't as good as a good increase in ram, but I've got no empirical data of my own to back it up.

[tesco]

Clocker says Dual-Channel didn't give him much better performance, but then again who needs 1.5gb of ram. :rolleyes:

I'd say go for more ram. ;)

[kaiweiler]

More ram is always a benefit. And depending on your motherboard you may be able to keep a gig running in dual channel and then a 512mb stick in single channel as well.
With the NF7-S, if I put 2x256mb sticks in slot 2 and 3 and then say a 512 stick in slot 1, the two 256 will run dual channel while the 512 will run single.

[Amarjit]

Cool. Any Socket 478 motherboards capable of that?

[clocker]

Originally posted by kaiweiler@5 July 2004 - 10:45
More ram is always a benefit. And depending on your motherboard you may be able to keep a gig running in dual channel and then a 512mb stick in single channel as well.
With the NF7-S, if I put 2x256mb sticks in slot 2 and 3 and then say a 512 stick in slot 1, the two 256 will run dual channel while the 512 will run single.
K,
Have you actually run any benchmarks with the RAM installed in different slots?

I did and saw no difference whatsoever.
There seems to be disagreement as to which slots on the NF7-S are dual-channel enabled, so I tried three different arrangements ( 2&3, which is what the manual tells you to do, 1&2 and finally 1&3) with similar ( not identical, but close) benchmarks.

I wonder what the deal is?

[kaiweiler]

Actually I emailed Abit about the issue you are speaking of, because I as well tried switching the ram around into various different arangements. The email I recieved stated the fact which I posted earlier. That if I were to put 2x256mb sticks in slot 2 and 3 and then a 512mb stick in slot 1, the two 256 will run dual channel while the 512 will run single channel by itself. Slots 2 and 3 are for running in Dual channel. As far as the Abit representative said anyway.

[clocker]

And?

Have you tested at all to see if that is correct?

[kaiweiler]

Originally posted by clocker@5 July 2004 - 17:57
And?

Have you tested at all to see if that is correct?
As you said before there were marginal benchmark increases, almost enough to just say it was a fluke. Dual channel does not seem to affect much at all, if anything

[clocker]

So it wasn't just me.

Good.

[lynx]

I think it is mainly that the underlying bus structure and cpu chip simply can't handle the data flow. Remember that although dual channel effectively gives 128-bit bandwidth, the processor still only has a 64-bit data bus.

The Athlon 64 (939 and 940 pin) chips seem to get much higher memory bandwidth with dual channel, presumably because the cpu chip itself has a 128-bit data bus.

As for "more memory always gives better performance", this depends on whether you are using the memory you have at present. If not, Windows will simply use the extra memory as disk cache, and unless you are using a lot of disk-intensive processes the benefits are going to be marginal.