how to tell if running dual channel ddr?

[mugicha]

ok possibly dumb question here but here goes. i'm a tech at a computer store and this guy bought an hp today (p4 2.8 ht 800mhz fsb), checked the specs on the mobo and it said it would support dual channel ddr. so he bought 2 512 sticks of pc 3500 we put them in the color coded slots (which i'm assuming indicated how to pair them) and he asked 'how can i tell if the dual channel ddr thing is working?' and i was like....hm good question. checked the bios and nothing explicitly said it there, although memory was recognized as pc3200 and fsb recognized as 800mhz. ran sandra 2003 memory benchmark on it and it said he was getting 4.2 gigs per second memory bandwidth, which is above what he would get with a single channel of pc 3200 (right? it would be like 3.2 or something...yes?) but below the 6.4 gigs per second dual channel is supposed to give you (is that just a theoretical 6 gigs?). so this is my question: is there some utility you can run that says "system running in dual channel mode" or something, do you have to rely on a benchmark like sandra, or if the bios had more options would it show up there? how does one tell?

 

[badenglishihave]

hmm... mine says so when it boots up (a7n8x), right below the ram check. do you have a boot screen, or can you see the checks and registers as the system loads?