Core i7 = Core i3?
Core i7 = Core i3 ???
This has no sense! it’s not the same “technology”! Core i7 are far better! no? read on…
The first thing to notice is that Intel, as nVidia and many others use TradeMarks for their chips. These TradeMarks are not related to technology, performance-level, engeneering but only on MARKETING. Pure marketing.
Some examples
nVidia 9600M GT is just identical to nVidia 8600M GT. Or “brand” new GeForce GT 330M is identical to old-generation GT 230M, and correspond to desktop GT 130! nVidia’s marketing is great, at least!
Pentium was used by Intel for Pentium (P54), Pentium Pro, Pentium-II, Pentium-3, and then Pentium-4 (netburst), Pentium-M and reappeared as Pentium for both Core Solo/Duo based processors and Core2 Duo based processors. Penitum is just a TradeMark used on different processors architecture, and it’s not related to any kind of technology.
And Core i7 = Core i3?
That’s the new Core i7 MacBook Pro, a 2.66Ghz 2-cores 4-threads, that takes it’s TradeMarked name from desktop Core i7, that is just twice bigger (and faster) : 4-cores 8-threads with faster frequencies and twice cache-size.
So the Core i7 mobile CPU that is on MacBook “Pro” is essentially half the Core i7 desktop CPU that is on iMac 27″. Same TradeMarked name, but half the raw performance-level! Cool!
In fact the laptop Core i7 share it’s genetics with low-end desktop Core i3, 2-cores 4-threads, that have better frequencies but no Turbo boost, and offers exactly the same performance-level. This is the point to use TradeMarks.
Why is it disappointing?
It’s because with Core2 (core microarchitecture), Intel plays the game fairly, a laptop Core2 Duo 2.8Ghz was on the same performance-level of a desktop Core2 Duo 2.8Ghz, with same bus, same number of cores (and threads), so when you bought a Core2 Duo at any frequency, wether it’s desktop or laptop, you know which performance-level to expect, your not paying for a TradeMark but for a result.
Now, with mobile Core i5 and mobile Core i7 on new MacBook Pro, you are paying for a TradeMark, not for the performance-level you are expecting, seeing same brand processors on your iMac or on desktop PC.
And it really show: even Apple have to compare Core2 Duo 2×2.8Ghz to Core i7 2×2.66Ghz (4-threads) to show 10% benefit on Apple’s Aperture 3, that is theorically multithreaded. These 10% is what a Core2 Duo 2×3.06Ghz will give you on Aperture 3, meaning that Core2 Duo 2-core 2-threads 3.06Ghz of last-generation MacBook Pro is as fast for Aperture 3 that mobile Core i7 with 4-threads and Turbo-boost at 3.33Ghz?!? Non sense!
On the desktop, Aperture 3 is naturally far faster on Core i5 4×2.66Ghz (and Core i7 4×2.8Ghz) than on a Core2 Duo 3.06Ghz, and that’s why Core i5 and Core i7 are really worth the -little- investment on iMac 27″.
On the laptop, except for video encoding and processing, where the new architecture really fly, Core i7 is not so fast compared to Core2 Duo, and may even be slower in many use case!
Don’t buy TradeMarks!
So avoid to buy TradeMarks, but instead compare internal specifications, and look at generic benchmarks sub-scores to buy what will give you more for your money. And remember that often a faster hard-drive (or SSD) will give you more performance on daily tasks than a faster CPU!
I will give you some example where a Core2 Duo might be faster than Core i7, even on the desktop 
