The processor is made up of billions of transistors, these form gates counters, an execution engine, cache, and other parts. The architecture is the way these parts are configured to work with each other. The more expensive processors , like the I7, have a more highly refined architecture.
Is a more highly refined architecture.a really poor investment? Not for Me!! But, for some people, anything past a $400 WalMart computer is a poor investment. I, my self, am a power user, and I strive to minimize user limitations on my builds.
???? The performance between i5 and i7 with HT off would be practically identical.????
This statement is an over simplification. Most programs are simple and are only written to use one core. For these programs, the above statement is true. But some programs and games are very complex and demanding, and are written to fully utilize hyper-threading and/or any number of cores they have excess to. The degree of benefit you see in a hyper-threaded or multi core processor depends on how well your software and the operating system are written to efficiently manage that specific extra resource. Hyper-threading has been around longer, so there is more hyper-threading friendly software out there than multi core, but there is no substitute for an additional core.
***A hyper-threaded processor's cores each contain an execution engine that manages, and shares its resources between, two logical processors. On a hyper-threaded core, you have two thread paths through this core, each path is able to use only about half of the cores processing power. With hyper-threading inabled, a 30% performance improvement is possible, but more than 10% is likely.
***A regular processor's cores each contain an execution engine that manages a single physical processor. On a dual core processor, you have one thread path through each core, each path is able to use 100% of the cores processing power. With use of a second core, an 80% performance improvement is possible, but more than 40% is likely.
With a hyper-threaded multi core processor, you have the best of both worlds.