i know this has been debated before but there is something i do not understand about dual channel memory. i had a memory and motherboard conflict recently and discovered that my PC was running in dual channel mode with 3 sticks of memory. i have 2-1GB sticks that would not boot my machine, so i tried putting some slower memory in the first slot with my memory in the next two slots. when i did this my PC said it was running in "dual channel intermediate" or something like that. After figuring out my booting problem the PC says running in "dual channel Asymmetrical" or something(with 2-1Gb sticks only). i may have those message reversed. Any way i thought dual channeling was only possible with an even number of sticks? and are there different types of dual channel? if so, what is the best?

Dual Channel Memory Works Just like Raid0

http://www.acnc.com/04_01_00.html

you must have even numbers
2sticks 4 sticks 6 etc

it writes different data to 2 seperate sticks at one time.
allowing theoretic doubling of Bandwidth.

but if one Stick fails you end up with heavy corruption and data loss.

only using 3 sticks will cause this undoubtably,
most BIOS/Hardware has error checking to stop odd numbers of Sticks being used in Dual Channel.

Dual channel doesnt mind having different size sticks of ram as long as
the 2 sticks in channel one match eg 2 x 1GB
the 2 sticks in channel two match eg 2 x 512MB

since the bios pretends you have two 1.5GB Sticks of DDR

I have added two 512Mb sticks in my computer which originally had two 256Mb sticks. I put only matching sticks in each channel:
Channel A: 2x512Mb (added)
Channel B: 2x256Mb (original)
No matter which way this is done, upon booting there is a timeout in Starting udev. One time I got a further message saying wait_for_sysfs: waiting for /sys/devices/pci0000:... (because I hit some keys during the wait maybe?) but usually says:
Wait time out, will continue in background. Then it will boot, acting slower than it should. When looking at the Physical Memory after boot, however, I see only 512Mb and everything is moving slower than it was with the original 2x256Mb only. It recognizes that the 1.5Gb are there in the GNU Grub screen saying:
(639K lower/1562815K upper memory) but then always times out at udev.

Booting under Windows XP gives me no problem whether the 512 sticks are in Channel A or B. I am having to use Windows to do all my work (yuk) since I need all the new memory for large designs.

Can anyone please help here?

Thanks.