help! dual channel w/2 different matched sets of RAM

[d1353L]

I am looking to upgrade my RAM configuration. I am running 2 x 256 sticks of PC3200 DDR in dual-channel mode. I have 4 total RAM slots. I want to buy 2 x 512 DDR matched sticks and put those in my remaining 2 RAM slots. As far as I know, with the 2 x 256 and 2 x 512 both in the mobo, if I keep the channels matched between each corresponding stick of RAM, I should still be able to run in dual channel mode. Therefore, I would have a total of 1.5 GB of dual-channel RAM.

I was told by a friend that this is not possible.

Can I run this configuration while still utilizing dual-channel mode?

Thanks.

system specs:
Dell Dimension 4600
P4 2.6 GHz w/HT
2 x 256 DDR PC3200
chipset intel i865PE

[wayout44]

Re: help! dual channel w/2 different matched sets of RAM

Personally I wouldn't do that due to the finicky way that dual channel memory controllers can be but you can try it and it may even work for you though do be sure to have the slowest modules in the first slot of each channel.