dual channel, why single mode?

[SanDiegoPC]

I have a backup system that has always run good...great in fact. But the BIOS gives that message on bootup ... why?

It has two identical RAM chips in it, and they are in the proper slots. (both blue)

 

[Mr Fox]

Probably you have a bad stick of memory .

Or try them in the other set of dimm slots.

that will tell you quickly

 

[n7]

What's it say in CPU-Z?

As long as you use the matching colors slots, you should have dual channel on the P5B-D.

If not, you might want to update the bios (do NOT use the auto update tool though; do it manually via floppy or bootable USB), or perhaps the RAM isn't really identical.

 

[SanDiegoPC]

-Z won't run on that PC at all. I'm thinking that the RAM really is not a matched pair. It all shows up (2.0G) but ever since I built it for backup purposes a year ago, it's always reported the memory that way upon startup.

Never bothered me none - that machine kinda just runs, off in the corner of the network untouched by human hands most of the time.

 

[sutahz]

It doesn't have to be a 'matched pair' to run in dual channel.
I'm pretty sure dual channel does nothing but give you a warm fuzzy.
Maybe there is a bios setting to disable dual-ch, but i doubt it. Why not put it in the yellow slots? I always put ram in the slot closest to the cpu.