Single Channel or Dual Channel

[ussff]

Maybe the dumbest question of the year... but here goes;

I'm trying to squeeze the best out of my skt 939 motherboard with AMD 64 x2 Dual Core 4200+, its an Asus A8N SLI premium with 4 slots for pc2700/pc3200 RAM, currently running 4x 512Mb of Corsair PC2700 value with WinXP SP3.

So getting it to its max of 4Gb means swapping out all 4 slots. I'm after better than "run of the mill" Cas Latency of 3-3-3-8 if I can get hold of it within ££££ reasonable limits

Simple enough task Dabs took my order for 2 kits of 2x1Gb OCZ PC3200 CL2 (2-3-2-5) Dual Channel, Platinum RAM early in Jan with a 1 to 3 days delay on stock, it seems like the best thing since value ram came to the market... but now its 1 to 2 weeks delayed - infact I'm not confident it will ever arrive!

I'm debating cancelling the order for some Geil Ram I have found but its single channel - is that because its a single stick and dual channel is activated by having 2 slots filled? My memory is a little sketchy around here... therefore 4x 1Gb Geil Ram will run Dual Channel! ...does it matter if it doesnt????

Also its got some strange timings advertised, instead of the standard specification advertisement i.e. PC3200 CL2 (2-3-2-5) as per the platinum ram, its says is...

Technology DDR SDRAM
Form Factor DIMM 184-PIN
Memory Speed 400 MHz ( PC3200 )
Latency Timings CL 3 8-4-4
Access Time 5 ns
Data Integrity Check Non-ECC
RAM Features Aluminium heatsink , unbuffered
Supply Voltage 2.55 - 2.95 V

The GE1GB3200BSC is a GeIL Value Single Channel PC3200 400MHz DDR SDRAM, Hand Picked 5ns GeIL DDR chips with Blue Aluminum heat spreader.

Now I know CL3 is not quite as good as the CL2 Platinum OCZ... but by the claim of "Hand Picked 5ns GeIL DDR chips with Blue Aluminum heat spreader" makes it sound like performance RAM.

So is the Geil single channel CL 3 8-4-4 (5ns RAM) worth going for now over the delayed OCZ PC3200 CL2 (2-3-2-5) - I'm comparing both against standard Kingston/Corsair value RAM of CL 3-3-3-8

[ussff]

Seem to have answered my own questions browsing NET - Dual Channel = motherboard supported to increase from 64bit to 128bit data path. Not dictated to by the memory module, but matched pairs give better compatibility... and my A8N is dual channel...

I've given up on the Geil as it might have had 5ns and fancy heat spreaders but CL 3 8-4-4 appears to be "value ranged" and miss quoted, elsewhere it is 3-4-4-8 which makes more sense...

I have found available stock of;

2GB OCZ Platinum XTC DDR PC3200 2-3-2-5 Dual Channel kit 2x1GB - VOLTAGE 2.6V-2.8V (EVP up to 3.0V) (£62.03 each inc VAT)

2GB G.Skill ZX Series DDR PC3200 DDR400 2-3-2-5 Dual Channel kit - VOLTAGE 2.6V-2.75V (£61.50 each inc VAT)

Both more expensive than Dabs.... but in stock! anyone tried either brand?

[Adrian Wong]

Originally Posted by ussff

Seem to have answered my own questions browsing NET - Dual Channel = motherboard supported to increase from 64bit to 128bit data path. Not dictated to by the memory module, but matched pairs give better compatibility... and my A8N is dual channel...

I've given up on the Geil as it might have had 5ns and fancy heat spreaders but CL 3 8-4-4 appears to be "value ranged" and miss quoted, elsewhere it is 3-4-4-8 which makes more sense...

I have found available stock of;

2GB OCZ Platinum XTC DDR PC3200 2-3-2-5 Dual Channel kit 2x1GB - VOLTAGE 2.6V-2.8V (EVP up to 3.0V) (£62.03 each inc VAT)

2GB G.Skill ZX Series DDR PC3200 DDR400 2-3-2-5 Dual Channel kit - VOLTAGE 2.6V-2.75V (£61.50 each inc VAT)

Both more expensive than Dabs.... but in stock! anyone tried either brand?

Dual channel means you get double the memory bandwidth = better performance.

Matched pairs are not a necessity but they can give you better compatibility. However, I think the compatibility issues have long been resolved. I have no problem mixing and matching even memory of different speeds.

[Ischemia24]

What happens if you've got two DIMMs with different capacities working in dual channel mode (say, one 2 GB and one 1 GB)? Is there any situation where you wouldn't get dual channel performance?

[Chai]

If I'm not mistaken, both memory must have the same capacity to get dual channel performance.

[Ischemia24]

I actually have a computer with one 2 GB DIMM and one 1 GB DIMM in the proper slots for a dual channel configuration, and the BIOS reports 3 GB of RAM and "dual channel" mode...
Maybe it's confused, or reporting dual channel mode but not performing that way.

[Adrian Wong]

That depends. Some chipsets allow you to use mismatched memory sizes, as long as the slots are filled in twos.