Memory speed on the new MacPro

Memory in the Mac Pro is server-quality memory. In particular, it is ECC memory.

According to actual testing by barefeats.com (and an Apple tech note), full memory speed is not achieved unless 4 modules are installed correctly (“quad channel”). Please see “SPECIAL REPORT: What Everyone Should Know about Mac Pro Memory Upgrades” at barefeats.com for details.

According to barefeats.com, the speed gain ranges from nothing at all, to 25% faster on the 3.0 GHz model (slower CPU speeds will show less of a difference). Since the Mac pro is a rather expensive workstation suitable for users who need the performance, slowing its speed with inappropriate memory selection and/or installation is self-defeating.

The Mac Pro uses two memory “risers”. For quad-channel memory performance, the memory needs to be installed on both risers in pairs (eg 2 X 1GB on one riser and 2 X 1GB on the other riser, and in matching slots).

The following memory configurations (installed appropriately) allow peak speed:

• 4 X 512MB
• 8 X 512MB
  
  
• 4 X 1GB
• 4 X 1GB + 4 X 512MB
• 8 X 1GB
  
  
• 4 X 2GB
• 4 X 2GB + 4 X 512MB
• 4 X 2GB + 4 X 1GB
• 8 X 2GB

Note that the base memory configuration offered by Apple will not allow top performance:

• 1GB (2 X 512MB)

In other words, anything but the default 1GB setup is OK.