Core-i5 vs Core-i3

Is there a significant difference between the two in terms of speed if you don't constantly run multiple movies or multitask with photoshop and moviemaker etc? There seems to be a big price disparity between the two in laptops.

 

The significant difference between i3 and i5 is the lack of turbo boost on the i3. While TB gets a lot of press and benchmark 'cred', it remains unproven in the real world.

TB is limited in terms of max mhz uptick, time, power drain, heat, and cores in use. People estimate that real-world users may see occasional throughput improvements of 5-10% for very short periods of time. Also, every time an i5 goes into TurboBoost, it will immediately downclock as necessary (below the rated nominal clock speed) so that the whole CPU can cool down. The sacrifice you make with the downclock/cool down part of the cycle might be MORE than you can ever hope to gain with the upclock.

The big boys like Adobe and Microsoft haven't said a word about how TB might improve the operation of their software (CreativeSuite, Visio/Access/SQL, etc).

IMHO laptops will continue to be I/O bound by disk and graphics throughput. So if there is any price premium for an i5 over an i3 it may not be worth the $$$.

Within the same generation of CPUs, the i3 and i5 are pretty close to identical.

Even without TB the iXXX generation of CPUs are said to offer superior performance (@ identical clock speeds, 30-40% 'better') when compared to C2D chips.

A minor downside of i3, i5, i7 is their requirement for DDR3 ram. DDR3 is still more expensive than DDR2 (getting cheaper though) and in many cases, DDR3 is no faster than DDR2. The main design point of DDR3 is and remains lowered power requirements. Only now after about 3 years on the market and new chipsets/CPUs is DDR3 starting to approach the nominal speeds of DDR2.