RAM in all the slots is a bad thing??

I have an ASUS P6T Deluxe Ver. 2 with (now), 6gb of RAM. Recently, while ordering another machine, I asked for 12 GB in all the slots and the salesman talked me against it. He said it's not good to fill all the slots. This is on another ASUS P6T and using Corsair Dominator 12800 @ 1600 mHz.

Can anyone confirm this?

It's not bad per se, but using all the dim slots sometimes requires more volts and there is no guarantee that you will be able to run the RAM at it's rated speed.

For example on my board I have 8GB of g.skill 1100mhz. With 4GB it runs at it's rated speed. But it simply will not run above 895mhz in an 8GB configuration.

Yep. I'd rather have more RAM at a lower speed than less RAM at a higher speed.

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Having said that, TomW - what do you need the 12GB for?

Do you use a lot of resource hungry apps like editing software / photoshop etc? For general usgae, 6GB is currently sufficient for the vast majority of usage needs.

smarteyeball said:

It's not bad per se, but using all the dim slots sometimes requires more volts and there is no guarantee that you will be able to run the RAM at it's rated speed.

For example on my board I have 8GB of g.skill 1100mhz. With 4GB it runs at it's rated speed. But it simply will not run above 895mhz in an 8GB configuration.

The salesman told me the 1600mhz RAM would have to be down sped to 1333. I guess my next question would be, if it's better to run 6GB at 1600 or 12 gb at 1333?

Thanks for the replies, guys.

Yes. I do a lot of Photoshop work. I let CS4 utilize my GPU a lot, though, and with the new box, I've ordered the GTX285 2GB RAM. I'll exchange it with my current 1GB RAM card. I'm not sure if it'll use more of the GPU RAM or not, since it apparently adds system RAM to the mix anyway.

So the consensus is that it's better to use all the slots and go with the other 6GB of RAM anyway, even if it's only able to run at 1333 (on 1600 rated) RAM?

Wow! After reading on the subject for the last half hour, (several great links! Thanks!), I think I'll wait because while the money isn't the issue over performance, the gains I get (and there are several, albeit small) aren't enough to justify the cost to not only buy 6 more gb, but environmentally, as well, in the form of not only 3 extra sticks of RAM in a landfill sometime in the future, but in the extra wattage and general power consumption.

Thank you again for all the awesome links, (the testing on Tom's Hardware Forum was the kicker), and responses. :)