Single VS Dual channel

[fabulouscoops]

Some interesting reading material

http://www.digit-life.com/articles2/mainboard/rmmt-ddr2-800.html

 

[Prot]

This reminds me so much of the raid 0 debate.........

It depends on what you are really doing, and yes, amd doesn't utilize dual channel as well as intel does, but if you belong to ocforums, you are no doubt trying to eek out every last bit of performance you can without breaking the bank, so that's why most people here run dual channel. Sort of off topic, but anyway, when I had my Thunderbird, I saw more of a performance gain by running tight timings with stock or mild clock speed compared to running loose timings and higher clock speeds.

 

[youngbuck]

That is currently a big debate in and of itself. Looser timing and higher clock speed, or tighter timings and lower clock speed? It seems to me that so far it is platform specific, but there are trends to be observed and recognized that throw wildcards in the mix.

 

[AlabamaCajun]

My money is on buying some nice low lat DDR2-667 and getting some nice OCs out of it or cheap 800 for speed. We spend a lot of money and wasted time beating up ram when we could just get the cpu to higher clocks and drop the ram to looser lats.

 

[Enablingwolf]

Single VS Dual channel

If you have it (dual channel) use it. Otherwise you can ramp up the single channel RAM to meet the difference % amount in dual channel pretty easy.

The later dual channel setups are hard to beat in how they go past single channel tech. It is more the technology then the actual single vs dual channel RAM though.

 

[shadowdr]

To me the biggest difference is the ability to run 1t on an AMD system with 2 gigs of ram. The 754 will not do that and is in fact no better then the XP. My biggest dissapiontment was upgrading from my NF7 to a 754, as soon as I ran the benches I realized that it was scoring about the same as the XP system. When I added a second stick it was even worse because of the 2t timing it had to run. If you run F@H it is a big difference between 939 in dual channel and 754 in single weather or not the 754 is 1t. Super Pi is also another indication that dual is better. At 32m the 754 would do 36m 11s while the same ram in a 939 dual channel will finish it in 28m 30s.

 

[Section8]

That is currently a big debate in and of itself. Looser timing and higher clock speed, or tighter timings and lower clock speed? It seems to me that so far it is platform specific, but there are trends to be observed and recognized that throw wildcards in the mix.

Yes in this debate bandwidth is about the same between the 2 but with the looser timings you get much more headroom for your OC so your Processor get a huge boost

 

[Serlant]

So lets say someone buys two 1GB sticks, he would be better off using them as 2GB in single channel as opposed to 1GB in dual channel? Atleast in the real world?

WHAT?
did i miss read or get something wrong? if i run my 2x 512mb sticks of ram in dual channel i've got 512mb of ram thats twice as fast as opposed to 1gb of ram thats half as fast?

 

[brakezone]

If you have 2 X 1GB sticks of ram, if you set it up in duel channel or single channel, it will still provide 2 gigabytes of memory.

Duel channel is always better when it is stable because the memory controller is using 2 64-bit memory controllers to form a 128-bit interface to the memory cells, where single channel uses 1 64-bit memory controller to interface with the memory.

 

[>HyperlogiK<]

Surely there must be some benefit to systems using older memory, say you have a whole bunch of PC2100 or PC2700, or slow DDR2 and wish to build a folding or backup games machine couldn't running DC be more worthwhile is such cases?

 

[GuitsBoy]

Really? I though in order to run dual channel, two 1GB sticks sum out to just 1 GB. If two 1GB sticks will come out to 2GB no matter if you run single or dual channel, the of course it would only make sense to run dual channel.

I though dual channel was akin to raid 1. Sounds like its actually closer to raid 0.

 

[MattCoz]

I though dual channel was akin to raid 1. Sounds like its actually closer to raid 0.

No reason to have redundancy in your RAM, dual channel is all about performance.

 

[Prot]

Really? I though in order to run dual channel, two 1GB sticks sum out to just 1 GB. QUOTE]


This is wrong. 2 gigs is 2 gigs and 1 gig is 1 gig, no matter what configuration you have the memory sticks installed. You don't lose capacity by installing them in dual channel, hence, if your hardware has dual channel capability, there isn't much reason not to take advantage of it.

This isn't meant to be disrespectful or anything, but I have seen the misinformation about losing capacity in dual channel before. There is a very good sticky explaining about memory controllers being the key to dual channel and how on some motherboards, it is possible to run dual channel with three sticks if they are installed correctly.

 

[GuitsBoy]

This isn't meant to be disrespectful or anything, but I have seen the misinformation about losing capacity in dual channel before. There is a very good sticky explaining about memory controllers being the key to dual channel and how on some motherboards, it is possible to run dual channel with three sticks if they are installed correctly.

I understand. I did quickly read through many of the stickies, as well as the dual channel page on wikipedia, however when you've already got the misconception in your mind, you read what you want to. Anyway, thanks for straightening me out.

 

[AlabamaCajun]

Running slower ram yields higher efficiency but still at a lower bandwidth. It's a curve that you can see in Sandra as you play timing albeit a synthetic test.

Running two sticks of 512 in single channel will be slower than 2x512 in DC due to slower command timing and hight lats needed to access 2 chips on the same channel.

 

[kbtat2]

There is a very good sticky explaining about memory controllers being the key to dual channel and how on some motherboards, it is possible to run dual channel with three sticks if they are installed correctly.

On my NF7-S I ran dual channel with three sticks. I had 2-512 and 1-1 Gb and it ran in dual channel.

 

[largon]

Running two sticks of 512 in single channel will be slower than 2x512 in DC due to slower command timing and hight lats needed to access 2 chips on the same channel.

Single vs. dual channel does not affect CMD latency not any other timings, the difference is in the width of the accessable memory. SC offers less bandwidth only because the memctrl is limited to access one 64bit wide "rank" at a time, thus halving the available bandwidth compared to dual channel allowing a simultaneous dual-rank (2x 64bit) access. "Rank" is a group of memory chips effectively operating as a RAID 0 array; the most popular (cheapest) practice is to group 8 individual 8bit wide chips together. The whole rank is accessed at the same time when memory is read/written, meaning 8 chips are always read/written at the same time.

 

[Gillbot]

socket A benifits from duel channel by a very small amount, like 300mb/s in sandra bandwidth tests.

I get less difference than that in my mem tests on my SN45Gv2 going from single to dual channel. Usually along the lines of less than 200mb/s.

 

[Airbornederekc]

dual channel is always the better way to go. there is a reason there are 2 channel and quad channel systems (on server boards they have quad). there is no reason to go single channel over dual channel. you get no performance gain, you are only goping to hurt your system. your taking away from the capabilities of that system and slowing it down.

 

[Gillbot]

dual channel is always the better way to go. there is a reason there are 2 channel and quad channel systems (on server boards they have quad). there is no reason to go single channel over dual channel. you get no performance gain, you are only goping to hurt your system. your taking away from the capabilities of that system and slowing it down.

Depending on the system though, if you have mismatched sticks, running larger volume of single channel may be better than running a lesser amount in dual channel.