Ram in THREE's? & 2 vs. 3 channels

Question

Level 1

102 points

Ram in THREE's? & 2 vs. 3 channels

Why would ram be sold in packaged sets of THREES?

Also how do you get to triple channel ram use and to how much advantage?

If it requires leaving one bank open, and stock Mac Pros come with 6 X 1GB,
you gotta throw somne away to upgrade, ugh

MP 8c, Mac OS X (10.5.7)

Posted on Jul 29, 2009 7:22 AM

Reply

Answer 1

The hatter

Level 9

61,031 points

Jul 29, 2009 8:37 AM in response to Steve Zavodny

3 DIMMs on each bank. That is why it is called DDR3 and triple-channel. It requires leaving one DIMM slot open, not a full bank.

Your upgrades are 6 x 2GB, or x 4GB, or you could have 3 x 1GB plus 3 x 2 or 4GB if you want to do part but not fully balanced upgrade.

Reply

Answer 2

Steve Zavodny Author

Level 1

102 points

Jul 29, 2009 12:38 PM in response to The hatter

so now I'm wondering about the balance. What do you know?
First I thought we were supposed to buy "balanced" packages of modules, balance meaning two,
and inserted in pairs, same slot each side. Now I am hearing of filling banks or buying packages of three. What do we gain by leaving what, one slot open? Then we have to toss away the stock ram to get it out of the slots? Would it be better to have 5 slots filled 2GB, 2GB, 1 GB, 1 GB, 1 GB, one empty? instead of the last one filled by 1 GB? etc? Thanks for your answers. How do you know these kinds of things?

Reply

Answer 3

The hatter

Level 9

61,031 points

Jul 29, 2009 1:04 PM in response to Steve Zavodny

The Mac Pro uses DDR3. "3" as in triple-channel.

Memory is configured on each Riser separately. If you do it "wrong" a utility will pop up and tell you even.

I would read some review aticles on DDR3 and triple channel.

And while this won't answer any of your pressing needs (maybe Barefeats and OWC has a chart of their own), some background helps.
http://www.barefeats.com/nehal04.html
http://eshop.macsales.com/Reviews/Framework.cfm?page=/Benchmarks/NehalemTests.ht ml

Also check Wiki. http://en.wikipedia.org/wiki/DDR3_SDRAM

http://www.anandtech.com/memory/showdoc.aspx?i=2989

http://www.xbitlabs.com/articles/memory/display/corsair-ddr3-1600_9.html#sect0

Oh, and read the booklet, it tells you how to follow the numbers to fill DIMM slots (1.....8) in sets of 2, 3, 4, 6 or 8 DIMMs.

Reply

Answer 4

Steve Zavodny Author

Level 1

102 points

Jul 29, 2009 8:48 PM in response to The hatter

The hatter wrote:
Oh, and read the booklet, it tells you how to follow the numbers to fill DIMM slots (1.....8) in sets of >2, 3, 4, 6 or 8 DIMMs.

The "booklet" that's on line? cuz there is no other I have.

Thanks I will do my homework on this.

Reply