The news no one at Apple wants to hear? The new entry level MacBook might be slower than the old one. According to Primate Labs Blog, that might be true. The low power Penryn, was more or less forced on Apple by Intel but does offer significant benefits in terms of power consumption and heat dispacement.
The real culprit, according to the blog (and common sense) is the lowering of the level 2 cache on the entry level Penryn processors from 4mb to 3mb. While the higher end processor also got 1Mb of level 2 cache lopped off, the processor speed makes up the difference.:
Despite having a slightly faster processor, the smaller L2 cache of the Penryn processors means the base MacBook (Early 2008) is slower than the base MacBook (Late 2007). If you’re considering buying a base MacBook, you might want to shop around and see if you can snag an old one rather than a new one.
Of course, the high-end MacBook (Early 2008) is faster than the high-end MacBook (Late 2007); it seems the increase in processor frequency is enough to overcome the smaller L2 cache in this case.
Overall the new MacBooks, like the new MacBook Pros, don’t feel like an incredibly compelling upgrade. Sure, the MacBook Pro has a multi-touch trackpad, but the MacBooks don’t and sure, the new Penryn processors are cooler and use less power, but at an apparent hit in performance.
If you do want to buy an "old" one, Amazon has them for a limited time and they are marked down considerably ($919!).