1 gig RAM + 256 MB = worse?

[severtki]

Just upgraded from 512 MB to 1 gig (2X512), running at dual-channel. I've got an Epox 8RDA3I Pro board, which has one more memory slot available.

With 2 sticks of 256MB lying around, would I be OK putting one in the third slot for 1280MB memory, or will this drop me to single-channel and worse performance?

Documentation stinks and is not real clear about this.
Thanks in advance,
Kirk

 

[AMDCrazy]

No you gotta use matched pairs for dual channel. Got to be that same type of memory 2x512 2x1gig etc. You can use another slot but you won't have dual channel capabilities.

 

[severtki]

That's what I figured, but the documentation seemed to imply it would still be dual-channel with the 3rd. Thanks for the confirmation.

 

[ElTorrente]

Why don't you just put it in and see what happens? Takes about 30seconds or so.

 

[JEDIYoda]

Thats what most guys do....

Stick it in and see what happens....

yep it usually takes about 30 seconds.....

what are we talking about here......lol

 

[severtki]

Of course that's what I should have done right away, but just blew out a motherboard, so I'm a little extra cautious about doing ANYthing in the case right now.

Added the extra stick and it couldn't handle the faster timings so Windows wasn't stable.

FYI, HOWEVER: boot process reported dual-channel WAS active, so with a faster memory stick, this scenario probably WOULD be fine.

 

[Spacecomber]

On the Epox 8RDA3+ motherboard that I have, adding a third module still means that the motherboard is running in dual channel mode. So, you'll need three matched modules for this to work properly.

DIMM slots 2 and 3 share the same memory bus and DIMM slot 1 is dedicated for second memory channel bus. So, as long as you are using DIMM slot 1, plus either or both DIMM slot 2 and/or 3, you are running dual channel.

 

[Peter]

This is NForce2. That chipset needs to pull those tricks for its 3-DIMM layout to work in dual channel at all - but it doesn't have a performance advantage anyway.

All other chipsets, as well as AMD's CPU integrated RAM controllers, require symmetrical population of the RAM channels.