It doesn't appear like there is much of an improvement at all - none in fact - in the single processor line-up.
That is a strange hypothesis given the rash of MHz junky posts that litter this and other Mac Pro threads. (e.g., "I want fewer, faster cores" ). The old and new single package line up (in "entry to top end" order )
Old 2.80 , 3.20 , 3.33
New 3.60 , 3.20 , 3.33
In the old line up, MHz junkies needed to buy the most expensive option to maximize clock speed. In the new line up, MHz junkies only need to buy the entry level model to maximize clock speed. There is probably a $1000 reduction in price for them. I would say that is a "feature" that many will buy.
In fact, if a user wants the fastest base MHz clock rate of the single and dual package models, then the entry level one, 3.6GHz, will be the fastest.
Comparing Hz is only transparent when the architecture is the same. Once change arch then it is increasingly an ineffective "apples to apples" metric.
The other fundamental problem is that people confuse instruction sets with architecture. The same instruction set can be implemented by two different architectures. Even multiple architectures implemented by the same company.
If you bother to drop down into the actual architecture and are concerned with real throughput on modern applications then the L3 cache is larger and ring bus connected to support speeds like 3.33GHz better for 6 cores. Likewise, there are 4 instead of 3 memory channels so can stream data faster (if don't pick a bonehead memory layout). The branch prediction and instruction fetching (new decode cache) are all substantially improved. While it may look like the mid and top tier clocks are the same the actual throughput through the core is likely 10-15% higher on average and much higher on more than a few applications. That is the problem with looking at single somewhat superficial characteristics to make large purchasing decisions.
And even for the MHz junkies, the E5 1660 will likely "Turbo" up to match the 1620 in speed. So if get your thrills running Mac Paint in Sheepshaver (or whatever last century software addicted to ) it will be just as fast.
Similar to the dual package models across old and new models (if drop down to low number of cores of previous generation the clock frequency goes up). MHz junkies should be looking in the "Turbo" column, not the base rate column, if primarily buying a machine just on MHz.
The dual package models will obviously be better because end up with 4 more cores. Even if the architecture was the same (which it isn't) that is just more "horsepower" to do multiple things at the same time. The myopic focus on single applications is humorous also. Two ( or more) applications where one (or more) are in batch processing mode and one is in interaction mode can consume multiple cores if. Anybody who "walks and chews gum at the same time" can soak up multiple cores in a box. [ For example, this rumor about CS 6 (
http://www.appleinsider.com/article...aperture_like_theme_new_3d_functionality.html ) states that Photoshop will have an
.... where "Save in Background" has been added, along with "Automatically save Recovery Information Every: with a choice of time intervals '
feature. There are numerous non esoteric actions that can happen in parallel if bother to implement them.
If get past myopically looking at cores and MHz then PCI-e v3.0 is substantially better than PCI-e v2.0. Even a limited set of SATA III connectors would be an substantive improvement.
Will these be classified as the first "post Steve Jobs" changes?
Only by the uninformed. The design parameters for the upcoming Mac Pro were finalized probably over a year ago. "Post Steve Jobs" is likely 1 - 2 years from now for the fundamental design constraints.