Is 2 better than 1? DDR RAM ISSUE ?

[leo888]

Anyone know anything about dual channel, I heard that if you put 2 x 256MB PC3200 or PC2700 is faster than 1 x 512MB PC3200 or PC2700. If this is true than I would buy 2 x 256MB instead of 1 x 512MB, any suggestion guys ?

[roley]

Yeah, I have not seen anything about that on the review pages...it might be true....these things get complex and interesting.

However, there are issues with the number of banks available on the mobo etc. Some of the Gigabyte boards I work with only support 6 banks but give you 4 slots....so if you put doublebanked memory (eg Corsair 400MHz give single bank 256MB, double banked 512 and 1GB) in slot 1 and 3, you could only put a TwinX512 in slot 2 and 4 and so on...

It pays to be careful...particularly if your talking to techs that are unaware of it or are making standard assumptions...

The bank issue changes as you go from 333MHz to 400MHz as well according to the help emails I got from Corsair and Kingston.

Roley
Black Frog Tech

[uethello]

Tell us what motherboard you have. Not all mobos have dual DDR. nForce2 does, nForce3 doesn't and none of the VIA chipsets have it.

[Christian-Comp]

Coming from experience on dual channel.
I have an Albatron motherboard and the requirements on this one is (for dual-channel) 2 sticks of memory. When I took out one of the sticks, it slowed tremendously. It ran without 2 sticks, but it was pretty slow (in comparison). The chips in dual channel ran 2x(2x200) or 800mhz. In single channel mode, the one chip ran 2x200 or 400mhz. Kinda like swapping out a P4 3.0 for a Celeron 1.5.

[leo888]

I have a Asus P4G800-V mobo, you think it will support for dual channel? And by the way thx for the tips, I pretty much have an ideal of how dual channel works.

[dejha]

if you read through the numerous reveiws and benchmarks online, you'll see that running dual channel does give a boost, but in the area of 3-5% on most applications. Mostly it comes down to cost - if it cost you the same and your board supports it you might as well - but the fact is it costs quite a bit more and you lose another memory slot. Your better off saving the extra cost and putting it toward more memory. I got 1 GB for bout $20 more than the cost for dual channel 512MB

[dejha]

ohh and just as a note don't beleive this guy saying that it's comparing running 800mhz to 400mhz - that just a load of crap. mostly it makes the board look at them as a single chip, theby reducing latencies and the need for seperate calls for the memory addresses. I wouldn't even suggest dual channel until your looking at a GB or more, as lower memory configurations see minimal gains in this area since they have such low latency chips on the market up to 512MB, just buy a low latency mem chip and tweak the setting in your bios to match

[roley]

To get full 800MHz or 1000MHz FSB support requires a CPU designed for it...(excl overclocking which I dont know well)

eg Athlon 64 socket 754 = 800MHz, Athlon 64 socket 939 = 1000MHz and so on.

=========

dejha has a point, everything about memory and latencies etc is cumulative...you are looking at big cumulative effects and less short term wow...a lot of computer improvements are like that...the wow factor somtimes appears maybe because people wait for reasonably long periods between upgrades and the technology has moved ahead quite a lot...thus seeming much better than in fact it was at the time compared to the last improvement.

=========

I think he also rightly points out the benefit in considering high quality 'single channel' solutions as opposed to dual channel just because the board supports it.

Also, he is right about quantities being important...that it may be better value to buy more higher latency, 400MHz dual memory (eg Kingston CAS3) than less ultra low latency 400MHz dual memory (Corsair CAS2); for similar prices( 1GB vs 512MB etc).

roley
Black Frog Tech