Intel’s Core i5 and i7 processors are faster, more power efficient, and better equipped for modern computing than any others on the market. The i5s and i7s have made their way into a huge number of laptops and desktops. Like most computer components, there are dozens of models at each tier to choose from, and it can get a little overwhelming.
This guide is designed to help you decide whether you need the extra technological enhancements provided by the Core 7, including better integrated graphics, faster clock speed, and hyper threading, or whether an i5 will suit your needs.
It’s worth noting, before we get started, that we’re talking specifically about Intel’s sixth-generation Skylake chips here. A lot of the information applies elsewhere, but the newer chips tend to provide noticeable feature and performance improvements over previous generations. You won’t save a lot of money buying Haswell chips either, and all but the most experienced builders will want to stay away from the early Core i5 and Core i7 offerings.
Hyper-Threading means that each core on the processor is capable of handling two processing threads instead of just one. These “threads” are used by software to manage multiple tasks simultaneously, rather than queuing everything up for execution one-by-one.
Windows will actually detect extra threads as physical cores, and software will use them as such, but the performance gain is only a fraction of what an extra physical core will provide. Still, the extra threads are useful in demanding software.
Hyper-Threading is not typically found on Core i5 desktop chips. It is common on Core i5 mobile dual-core processors. All Core i7 processors have it, which means they all can handle twice as many threads as they have cores. While nice to have, the feature’s impact is very dependent on software. Only applications specifically designed to take advantage of multiple threads will see a performance increase. The feature is most useful to people who run productivity applications, including photo and video editors.
The clock speed is a measure of how quickly each core on a processor can handle operations, generally speaking. It has become less relevant as a general performance indicator over the last decade because different processors handle operations at a different rate even when they have the same clock speed — but we’re comparing just Core i5 and i7 processors here. They’re built on the same architecture, so a higher clock speed means better performance.
Here’s the thing, though — quad-cores sometimes have lower clock speeds than dual-core chips. This is most common in mobile chips that must squeeze into a tight power envelope. What does this mean? A dual-core with a high clock speed will beat a quad-core with a low clock speed in applications that don’t use many cores. However, the quad-core will be quicker in applications that do. If the quad has more cores and a higher clock, it’ll always be quicker.
In addition, Intel Core i5 and i7 processors are equipped with a feature called Turbo Boost. Turbo Boost will increase your clock speed when power use is low otherwise, or some of the cores are sitting idle. This can boost performance in certain situations. Quads tend to boost more aggressively than dual-core processors, and desktops more aggressively than laptops.
With all this said, a quad-core Core i5 or i7 chip is almost always going to feel as quick or quicker than a dual core. Why? Because the kinds of applications that only use one or two cores (like a web browser) are almost universally easy to execute. Applications that are demanding are almost always coded to use multiple cores well — and frankly, it’s a fault on the part of the developer if they’re not.
The Core i7 processors have, in modern terms, what seems like a very small increase in cache over the Core i5 processors, only a 2MB difference. When it comes to cache, this number, smaller than most MP3 files, is actually huge, marking one of the most important differences between the two series of chips.
Cache is like a bag you can drop extra items you need a lot into, allowing you to grab them quickly when you need them without having to ask RAM for them. If you have a small bag, you won’t be able to drop much in it, and when it fills up you’ll have to go store items someplace more permanent. The time needed to do that slows everything down.
Not only do Core i7 processors have a greater amount of cache than Core i5 processors, they’ve also been designed to make full use of the extra memory afforded to them, speeding up repetitive processes and lowering power use and memory demands.
Heat and power are the limiting factors of performance for all processors, and they determine the advertised characteristics of each chip individually, a practice known as binning. Rather than producing chips that work towards a certain speed or functionality, Intel produces as many high-end chips as it can. After production is finished, the chips are measured, and then placed into models (sorted into bins, in other words) based on their ability to achieve the listed speed and market demand.
For the most part this isn’t a huge factor when deciding whether to choose a Core i5 or i7, as all power supplies generate enough energy to power an i7 processor, and the included cooling will support the chip as long as it isn’t over-clocked. That said, a computer with a Core i5 chip will have lower power and heat than a computer with an i7 chip.
While we’re on the subject of Core i5 and Core i7, it’s worth mentioning Intel’s Core i7 Extreme lineup, also known as Broadwell-E. These massive chips extend the power of the highest-end Core i7 chips with even more cores — up to 10 in the Core i7-6950X — better overclocking controls, and expanded support for multiple GPUs.
These chips sport almost twice the pins of a standard Core i7 chip, and require a different motherboard chipset — called X99 — than all of Intel’s other processors.
Only savvy, high-end builders looking to spend a couple grand on a new computer will even look at these enthusiast processors. These processors are overkill for most users.
When it comes to price, there’s a clear difference between the two series, with some of the Core i5 chips starting below $200. The Core i7 chips run a premium, starting at $300 and climbing from there. While it’s common to find processors on sale for a significant discount with a compatible motherboard, expect to pay at least $400 for those two parts.
If you do go with the Core i7, it’s not unreasonable to also want to pay $30 or more for 8 GB of memory, and at least $200 on a graphics card if you really want to reap the benefits of your pricey processor in games.
For most users, the extra features and processing power of the Core i7 won’t be worth the cost difference between the two tiers.
While there are a lot of factors in determining overall system performance, a Core i5 processor won’t be the bottleneck in a large number of systems, both custom and pre-built. Most people, including gamers, will find a Core i5 quad-core perfectly adequate.
A Core i7 makes sense only for users who don’t mind paying a premium for more power, or users who often run extremely demanding software. For example, shaving a few seconds off every minute of encoding 1080p video adds up if you regularly encode projects that are a couple hours long.