can you explain dual channel memory?

[macdawg]

does dual channel mean its 400 mhz ram or higher instead of dual channel ram which is 333 mhz or lower?

is it that big of a difference?

thx

 

[Nubius]

wha? 400MHz RAM is a completely different RAM from 333MHz

all dual channel means is it access both memory sticks at once instead of only one and then accessing the other until the first fills up.

It's anywhere from 5%-20% performance increase but it's nothing insanely noticeable in speed.

 

[Elbatrop1]

I have read about Dual Channel only giving an extra 1% to 5%. Either way, its pretty small.

A lot of people get DDR confused with Dual Channel. Nubius gave a nice explanation on Dual Channel. DDR just means that the RAM transfers data twice for every clock cycle. For example, if a stick of RAM is getting a clock pulse that is going at 200MHz, it will transfer data 400 times per second. This is how DDR RAM receives a frequency of 200MHz, but then it is called DDR400.

 

[macdawg]

I guess thats why my 400 mhz memory was listed at 200 mhz in everest home edition. (My P4 is 800 mhz FSB)

 

[Nubius]

I have read about Dual Channel only giving an extra 1% to 5%. Either way, its pretty small.

Yeah I've only seen it in one place as 5%-20% but like you said and I agree, it's minimal.

I guess thats why my 400 mhz memory was listed at 200 mhz in everest home edition

It's not technically 400Mhz though...200 is the actual MHz, DDR stands for DOUBLE data rate, because it does cycles on both the rise and fall of data so it's 200x2 = 400, that's how they get DDR400 otherwise known as PC3200...it's given that because it delivers approx 3200mb/sec bandwidth....however in newer systems the bandwidth is optimized so on AMD64's it's like 6400mb/sec, sometimes more depending on the memory controller.

it will transfer data 400 times per second. This is how DDR RAM receives a frequency of 200MHz, but then it is called DDR400.

The fact it's "Double" data rate is why it's called DDR400, not because it's dual channel which technically DC has nothing to do with the RAM itself besides them having to be a matching pair.

It's all up to the mobo and CPU to actually run dual channel