Early '08 - RAM config with 4GB modules

[lannister80]

I'm thinking about grabbing some 4GB modules for my Early 08 Mac Pro. Is this the config I should set them up in?
(and yes, I've looked at the RAM config guide everyone knows about, but it doesn't include 4GB modules)

Riser A (top)
4GB
4GB
2GB
2GB

Riser B (bottom)
2GB
2GB
1GB
1GB

The only reason I ask is that I didn't know if it was better to have the 2GB pairs matches against each other in the riser slots (across cards) to get full interleaving. So another config would be:

Riser A (top)
2GB
2GB
4GB
4GB

Riser B (bottom)
2GB
2GB
1GB
1GB

or

Riser A (top)
4GB
4GB
2GB
2GB

Riser B (bottom)
1GB
1GB
2GB
2GB

Thanks!!

 

[Tesselator]

(and yes, I've looked at the RAM config guide everyone knows about, but it doesn't include 4GB modules)

Just use the logic of the guide. Pretend your fours are twos and your twos are ones, etc.

 

[gugucom]

Just use the logic of the guide. Pretend your fours are twos and your twos are ones, etc.

This would be difficult because he has only two 4GB modules. I would suggest the following:


Riser A (top)
1 - 4GB
2 - 4GB
3 - 1GB
4 - 1GB

Riser B (bottom)
1 - 2GB
2 - 2GB
3 - 2GB
4 - 2GB

 

[lannister80]

This would be difficult because he has only two 4GB modules. I would suggest the following:


Riser A (top)
1 - 4GB
2 - 4GB
3 - 1GB
4 - 1GB

Riser B (bottom)
1 - 2GB
2 - 2GB
3 - 2GB
4 - 2GB

Yep, that looks right to me. I realized that if I divided all the values of my modules in half that they would match "9A" on the RAM chart we all know and love. And that is exactly gugucom recommended.

Thank you!