So you are about to purchase a brand new pc, and the manufacturer gives you a choice of processor. You’ve heard that i7 is the best of the line (after all it is the highest number), but is there any reason to go instead with i3 and i5 now that intel fixed Sandy Bridge?

Core i3

Intel’s Core i3 processor line has always been a budget option. These processors remain dual-core, unlike the rest of the Core line, which is made up of quad core processors. Intel’s Core i3 processors also have many features restricted. The main feature that is kept from the Core i3 processors is Turbo Boost, the dynamic over clocking available on most Intel processors. This, alongside with the dual-core design, accounts for most of the performance difference between Core i3 processors and the i5 and i7 options. Core i3 processors also lack Intel’s vPro technology virtualizaton and AES encryption acceleration technology. These are features unlikely to appeal to your average user anyway, and are instead targeted towards enterprise users. Still, the lack of these features should be kept in mind.

One feature that Core i3 has – and i5 doesn’t – is hyper-threading. This is Intel’s logic-core duplication technology which allows each physical core to be used as two logic cores. The result of this is that Windows will display a dual-core Core i3 processor as if it were a quad-core.

Finally, Core i3 processors have their integrated graphics processor restricted to a maximum clock speed of 1100 MHz, and all Core i3 processors have the 2000 series IGP, which is restricted to 6 execution cores. This will result in slightly lower IGP performance overall, but the difference is frankly inconsequential in many situations.


Core i5

Intel used to split the Core i5 processor brand into two different lines, one of which was dual-core and one of which was quad-core. This was, needless to say, a bit confusing for buyers.

Thankfully, the behavior has stopped (for now). All Sandy Bridge Core i5 processors are quad-core processors, they all have Turbo Boost, and they all lack Hyper-Threading. Most of the Core i5 processors, besides the K series (explained later) us the same 2000 series IGP with a maximum clock speed of 1100 MHz and six execution cores.

In the i3 vs i5 vs i7 battle, the Core i5 processor is now obviously the main-stream option no matter which product you buy. The only substantial difference between the Core i5 options is the clock speed, which ranges from 2.8 GHz to 3.3 GHz. Obviously, the products with a quicker clock speed are more expensive than those that are slower.

NOTE: As of 2/20/2011, Intel has introduced a dual-core Core i5 called the 2390T. The T appears to be what designates it as a dual-core part. It is the only dual-core Core i5 as of yes, so hopefully Intel has introduced this as some sort of exception, as a return to the confusion of the first-gen Core i5 parts would be disappointing.


Core i7

The Intel Core i7 series has also been cleaned up. In fact, it has perhaps been cleaned up too much, because at the moment Intel is offering only two Sandy Bridge Core i7 processors. These processors are virtually identical to the Core i5. They have a 100 MHz higher base clock speed, which is inconsequential in most situations. The real feature difference is the addition of hyper-threading on the Core i7, which means that the processor will appear as an 8-core processor in Windows. This improves threaded performance and can result in a substantial boost if you’re using a program that is able to take advantage of 8 threads. Of course, most programs can’t take advantage of 8 threads. Those that can are almost usually meant for enterprise or advanced video editing applications – 3D rendering programs, photo editing programs, and scientific programs are categories of software frequently designed to use 8 threads. The average user is unlikely to see the full benefit of the hyper-threading feature. In the Core i3 vs i5 vs i7 battle, the i7 has limited appeal.

The IGP on Core i7 processors can also reach a higher maximum clock speed of 1350 MHz. As I’ve said before, however, this difference is largely inconsequential when measuring real-world performance.



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