Difference between Intel Core i3, Core i5 and Core i7 processors


3<5<7. Toh Core i3<Core i5, Core i7 bhi hua na?” – Curious me. Was quizzing a computer vendor on my last visit to buy a pen drive!

So, second in series of processor analysis, I bring to you the technical yet readable differences between the Intel Core i3, Core i5 and Core i7 processors. Absolutely right, Core i7 is more powerful than Core i5 and Core i5  is more powerful than Core i3. But what exactly makes them different? To explain that, I first need to describe two technologies:

1. The Intel Turbo Boost Technology: Intel Turbo Boost Technology helps deliver more performance when and where you need it. If the processor detects that it is below its power, temperature, and current limits, its clock frequency increases to boost performance for active processor cores.  (Processor Cores. What are they? Read my previous post). Optimization of available resources. So if you are running a multi threaded application, that requires more power the technology intelligently increases the clock frequency. And  if you are running a legacy application that is not multi-threaded the clock speed is increased further. Now for an analogy to this. Relate this to the problem of allocation of resources. Suppose you work for a construction company, and the company is working on construction of multiple buildings. With the available resources you have two options: Either divide the entire work force for different constructions or deploy some and keep a buffer. What Intel Turbo Boost Technology does is analogous to keeping a buffer. So you see that the Swimming Pool construction needs more labour, you direct the buffer to that. Or may be all except one building are complete, you direct the entire work force there. So what happens is that all work is completed in time and you make the best use of your available resources.

2.The Intel Hyper Threading Technology: This is the ‘HT’, you’ve seen over the Pentium 4 logo some years back. What this does is that, it allows multiple threads to be processed by a single core. But what’s a thread? I quote from the famous Wikipedia:

In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. (For more, check the link at the end of post).

More simply relate multi threaded applications to be multiple applications. I safely make that statement as many of the Intel Technologies videos use the same terminology. Since this is a technology we have also seen with the Intel Pentium 4 processors, this must be coming as a standard with all processors? No, not all processors use the Hyper Threading Technology, and it may be even that the processors without Hyper Threading Technology are faster than the ones with it. To understand that better, let’s analayse the working of different kind of processors.

Single Core Processors: Processors that processed  just single threads.

Single Core Processors with Hyper Threading Technology: Process Multiple Threads at single Time. The Pentium 4 stuff.

Dual Core Processors: Two threads are processed in two separate cores on a single processor. The important point here is that this isn’t Hyper Threading, since one core is processing only a single thread.

Quad Core Processors: The same technology as the Dual Core Processors, except that the Dual Cores as the name suggests have 2 cores and the Quad Core have 4 Cores. More Cores, more power!

Multiple Cores with Hyper Threading Technology: This is something really fast than any of the previous processors, I  have discussed through out the post. In such processors, every core on a multiple core processors processes 2 threads. So a Quad Core Processor with Hyper Threading Technology, can process 8 Threads at a time!

Now that you know about the different kind of processor technologies, the comparision between the Core i3, Core i5 and Core i7 becomes more easy to understand. (For specific clock speeds. Don’t forget to read the important note below). **

A Core i3 processor has 2 Cores, and it manages 4 Threads. Yes, it supports Hyper Threading but no Turbo Boost.

A Core i5 processor has 4 Cores and it manages 4 Threads. It doesn’t support Hyper Threading but it does support the Intel Turbo Boost Technology.

A Core i7 processor has 4 Cores and it manages 8 Threads. Yes, it supports Hyper Threading and Intel Turbo Boost Technology.

What’s also different is that the Core i7 and Core i5 processors have different cache sizes.  If you have little knowledge about cache, just take it for now that more the cache, more the speed.

**The comparison is for desktop processors with certain clock speeds. Cores on Core i7 can go up to 6, and hence number of threads up to a whooping 12. Mobile Processors, have different configuration of cores and clock speeds. But now being familiar with these technologies, you are ready to read between the lines of the technical specifications sheets.

As usual, before you leave, I request your feedback! 🙂