Penryn MacBook Pros: Performance Comparable, Battery Life Greater
Anandtech posts a lengthy review of the new Penryn-based MacBook Pros. Their review provides some objective data on the new laptops, as compared to the previous generation.
As described before, the biggest change in the new MacBook Pros is the use of a 45-nm Penryn CPU as opposed to the older 65-nm Merom CPU. Despite some differences in L2 cache, Anandtech found benchmark performance to be neck and neck:
Overall, the performance differential ends up being a wash - there are some cases where Penryn is faster at lower clock speeds, while others where Merom manages a win - much as we expected.
One measurable advantage of the new processors, however, is an extension of battery life, with improvements ranging from 7-15% longer than its predecessor, with an absolute increase in battery life of 37-67 minutes in their web browsing test.
It looks like Penryn is good for a 7 - 15% increase in battery life over similarly configured Merom systems. The improvement alone isn't enough to warrant an upgrade but it's a nice improvement over the previous systems given that you get it at no additional cost. Ah, the beauty of innovation.