MacPro RAM upgrade configuration

[R.Youden]

With the recent conversion rates I decided to order some RAM from across the pond for my MacPro and I got 4GB inc shipping for under £100 (£140 at crucial).

Anyway I have configured my risers as follows:

A:

512MB (stock Apple RAM)
512MB (stock Apple RAM)
Empty
Empty

B:

2GB (New RAM)
2GB (New RAM)
Empty
Empty

Now my machine flys, however when I look under "About this Mac" it says I only have 4GB, any suggestions as to why the two 512's are not being picked up?

Thanks.

 

[Tallest Skil]

I'd switch them. Put the two twos on the top riser and the two 512s on the bottom.

 

[R.Youden]

Thanks for that, can the system be that picky as to the exact order? I understand the principle of matching pairs but I am amazed that the order of the risers would have an effect.

 

[wpc33]

I thought you had to have the pairs matched vertically. With riser A & B both having 2GB & 512 MB

 

[hayduke]

If the swap worked, then yes your machine is that picky, but I wouldn't expect it. Did you put the new ram in the empty riser or did you swap it into the riser the 512s were in? You might have a bad riser if that is the case. Alternately, you could have fried two 512s during the install. Admittedly, both of these possibilities seem quite small.

 

[Tallest Skil]

I thought you had to have the pairs matched vertically. With riser A & B both having 2GB & 512 MB

Nope. You have to pair next to each other, but not across risers.