Anybody tell me the pro's and con's of using dual channel memory? My mobo supports this feature. What does it do? I mainly use the pc for Flight Sim, not sure if I would benefit from using it. Mick. (UK)

For DDR Ram to work you need to have two sticks of RAM the same speed and size installed. I'm not sure if this is correct but I think it doubles your RAM's bandwidth. Pretty much every application benifits from it but if you are happy with your curent setup you probbably wont need it.

Mattwizz3 : )

AMD K-7 600MHz & Asus K7v
256Mb SDRAM
80Gb WDC, 8Mb Buffer
128Mb ASUS Radeon A9550
Cyber Drive CD-RW DVD Combo
Spirit TV tuner

When referring to the CPU, it's called "bandwidth", but when referring to RAM, it should be called "throughput".

Running RAM in dual channel mode is unnecessary on a socket A system. It doesn't hurt, but there's really nothing to be gained by it. The reason is that if the CPU is running at 200MHz (400FSB), the bandwidth is 3200MB/sec. The throughput of PC3200 RAM at 200MHz is 3200MB/sec. If you run PC3200 in dual channel mode, the RAM throughput is effectively doubled to 6400MB/sec, but since the CPU's bandwidth is 3200MB/sec, the RAM's added throughput cannot be taken advantage of.

The story is different for the P4/800FSB CPU or the Athlon64 socket 939 CPU

Asus A7N8X-X
1800+ @ 8 x 210MHz
512MB PC3200
Asus Ti4200 128MB
WinME/WinXP Pro

Hopefully I'd be saying this a lot less often, You DO NOT!!! need two (identical) sticks of RAM, same speed and size installed to run in dual channel.

It is the board that has to support the feature not the memory.

B4 you criticize a bigger man, walk a mile in his shoes. That way, you're a mile away, and you have his shoes.

Ah yes, but the more we repeat ourselves, the better we get at it...lol

Asus A7N8X-X
1800+ @ 8 x 210MHz
512MB PC3200
Asus Ti4200 128MB
WinME/WinXP Pro

Sabertooth,
My MSI ms-7008 calls for the ram to be 2 matching cards for dual channel mode.
Jam,
So you're saying that for an amd chip system. What about a Intel p4 system? Mine is a 2.4ghz non hyperthreading chip.

I may be crazy, but I'm not stupid...

"When referring to the CPU, it's called "bandwidth", but when referring to RAM, it should be called "throughput"."

Not exactly true. Technically speaking bandwidth is what's possible vs. what actually goes through which is throughput. Theoretically, it is possible that increasing bandwidth can increase throughput if throughput has met the bandwidth. In this case you're right; that hasn't happened.

However, dual channel doesn't just double bandwidth; it also reduces latency because two memory controllers are available as opposed to one, so the chances of a memory controller being available when needed is increased, thereby responding faster.

It's no wonder therefore that enabling dual channel allows for increase in performance somewhat similar to having lower CAS latency RAM. But practically you are right that it doesn't amount to a whole lot most of the time. However, it is demonstrated in Half Life 2 dual channel does increase performance around 2-3%, but can be as high as 17% depending on the demo used. Interestingly, lower CAS latency demonstrates the same type of performance gain.

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2330&p=3

I would be interested in seeing if you'd see a somewhat small increase in performance on an Athlon XP 3200. I suspect this is due to lower latency, not increased bandwidth.

MCSE, MCSA Messaging, baby!

Many thanks for all your remarks, most helpful, Mick.