Recall that internal expandability was a feature of the Intel Mac Pro only. The same enclosure was used for the PowerMac G5, and most of the space inside was fo

Recall that internal expandability was a feature of the Intel Mac Pro only. The same enclosure was used for the PowerMac G5, and most of the space inside was for the cooling systems. There was room for a single extra hard drive and a couple cards and that was it. We're just going back to that, in an era when it matters less.