Please see the discussion of a rumored Mac Pro.
For new Mac Pro features / functionality, the rumor mills suggests the following.
UPDATE: with some shock, professional users have seen Apple disregard their needs by offering nothing new in the Mac Pro line at WWDC in June 2012. The Mac Pro is now almost 2 years old.
More efficient CPU chips having 8 cores (or 16 cores with two CPU chips).
Speed gains depend in some measure on which clock-speed options Apple offers.
For example, with the current Mac Pro the 3.46 Ghz CPU is not offered; you can’t buy a 12-core faster than 2.93 GHz — a loss of 18% on clock speed versus what is possible. Nor is there a 6-core 3.46 GHz option currently.
My upgraded 12-core uses dual 3.33 GHz chips which are 13% faster than the fastest 12-core that Apple sells. I upgraded before the 3.46 GHz chips appeared.
Bays and ports
We shall have to see if there are new goodies, like more than 4 bays, or extra bays for 2.5" SATA drives (e.g., SSDs), etc.
Once the Mac Pro sees Thunderbolt, and new far-cheaper Thunderbolt chip sets are out (this fall), the variety of Thunderbolt peripherals will explode, and the choices will expand, and prices will drop.
Native SATA III 6 Gb/sec ports
This will be a boon for a 6G SSD, but has little real-world benefit for fast hard drives (except perhaps on artificial tests and very specialized scenarios).
Good and useful for simple add-ons, more so over time. Not really a high performance expansion option, but a Very Good To Have and a worthy replacement for moribund Firewire 800.
PCI 3.0 slots
For higher performance of PCI cards. Since most cards don’t use the existing PCI 2.0 bandwidth fully, this is a “nice to have”. Still, there are some specialty cards that might benefit.
Potential for more addressable memory.
- The maximum installable memory depends on the number of slots.
- The maximum accessible memory depends on Mac OS X.
Today in Mac OS X Lion, Apple handicaps the existing 4/6-core Mac Pro to 48GB and the 8/12-core Mac Pro to 96GB instead of 64GB / 128GB (the same Mac booted into Windows can use the full amount). This is an Apple BUG.
And even today, Apple won’t sell you more than 32GB / 64GB, while you can go to 48GB / 96GB memory using OWC modules.
Faster memory controller
The new on-CPU memory controller allows higher processor efficiency, especially important for the new 8 or 16 core CPU chips (up from 6 or 12).
Apple could stick with 1333 MHz memory, or move to 1600 Mhz (20% higher bandwidth). In practice, the actual speed gains are generally minimal, as seen with the current Mac Pro using 1066 vs 1333 MHz memory.