Summary
Highlights
Intel's Core i3, Core i5, and Core i7 labels can be very confusing. Historically, simply labeling processors by gigahertz was also problematic, as a higher clock speed didn't always mean better performance. For example, the Pentium 4, despite higher clock speeds, was sometimes slower than an equally clocked Pentium 3 due to architectural differences. This led to a need for a new naming convention.
AMD attempted a 'performance rating' (P.R.) scheme in the early 2000s, but it still indirectly tied to clock speed assumptions. The 'megahertz war' ended when Intel introduced the Core series, which significantly outperformed predecessors at lower clock speeds, prompting Intel to shift marketing away from frequency alone.
A Core i3 is Intel's most basic option, featuring two processing cores and hyper-threading for better multitasking. It has a smaller cache, consumes less power, performs generally worse than a Core i5, but is more affordable.
The Core i5's core count is not as straightforward as 'n-1' from its name. Mobile Core i5s typically have two cores with hyper-threading, while desktop versions often have four cores without hyper-threading. Key features include improved onboard graphics and Turbo Boost for temporary performance enhancements.
All Core i7 processors have hyper-threading, making them suitable for heavy workloads. They show significant variety in core count (two in an Ultrabook to eight in a workstation), memory support, and TDP (10 watts to 130 watts). Core i7s typically boast more cache, faster Turbo Boost, and better integrated graphics. They represent Intel's best offerings for specific use cases but come with a higher price tag.
The 'i' numbers (i3, i5, i7) broadly signify 'good, better, best' within a given segment but are otherwise meaningless on their own. To genuinely compare CPUs, it's best to use tools like Intel's ARK to examine features, core counts, and clock speeds. Comparing processors within the same brand and product generation provides meaningful metrics.