Dual Channel Memory is no faster than single channel

[sondreal]

• I had an Ultra 1024MB DDR 400mhz stick in my computer.
• I replaced it with 1 GB (2 * 512) DDR 400mhz Dual Channel kit.
• When I run all memory tests the results are no better with the dual channel kit.
• I used Memtest 86 and tested all the sticks of memory and no problems showed up.
• Why doens't the memory test show better results for Dual Channel?

Thanks,

[David (PassMark)]

It might be that you have the RAM in the wrong slots. Or it might be that your MB doesn't support dual channel.

It would have been good if you posted the before and after numbers.

[lee_sov]

I recently ran the test on a machine with 2gb ram ( 2 x 1gb sticks) using dual channel, I then removed 1 of the sticks and ran the test again (only single channel) and received a higher rating! Dont understand how that can be, surely double the ram would produce a higher score?

[sondreal]

I'm using the Abit Av8 board. It says that the ram needs to be in slot 1 and 2 or 3 and 4 for dual channel to work. I have the ram in slot 1 and 2 and havent noticed any performance increase running the memory test.

[sondreal]

I orginally said the results were no better with the dual channel. I should have said they are barely better.

Here are the numbers:

1GB single channel:
memory allocate small block - 1923.8
memory read cached - 1077.8
memory read uncached - 964.5
memory write - 862.7
memory large ram - 186.5
memory mark - 370.8
passmark rating - 66.7

1GB (2* 512MB) dual channel:
memory allocate small block - 1943.5
memory read cached - 1090.3
memory read uncached - 972.1
memory write - 946.1
memory large ram - 219.7
memory mark - 382.3
passmark rating - 68.8

[David (PassMark)]

The allocate & cached memory test shouldn't be greatly effected because they don't use the full bandwidth of main RAM much.

Yes, your 5% to 10% increase does look a little low. I am not sure as to the reason. I wouldn't assume anything is wrong unless you sure much larger increases from other motherboards. (I don't have any numbers handy to tell you what you should expect from this type of comparison)