If you’re choosing a new PC – or even building one yourself – it’s vital to pick the right processor. If your CPU is too basic for your needs, you’re dooming yourself to sluggish performance. If you splash out on high-end power you don’t need, that’s wasted money that could otherwise go towards a fast SSD, a beefy graphics card or a luxurious display.
Here you’ll find our pick of the best desktop CPUs available today. Note that we’ve stayed away from mobile processors, as that’s a different market: when buying a laptop you’re typically restricted to one or two CPU options anyway, and performance must be balanced against other issues such as weight and battery life.
In the desktop market, things are much more flexible; within reason, you can choose whichever processor you want. Here’s our pick of the best contenders, to suit all needs and budgets, so you can buy in confidence and enjoy a slick computing experience.
How to choose the perfect CPU for you
Is Intel better than AMD?
For the past few years, processors made by Intel have been more powerful – and much more popular – than those made by rival AMD. However, AMD’s Ryzen processors have turned that around: they’re powerful CPUs at a tempting price, and an excellent alternative to Intel.
What sort of motherboard do I need?
If you’ve chosen an AMD Ryzen processor, you need an AM4 motherboard. There are plenty to choose from, using different onboard chipsets to provide different features (such as varying numbers of PCI-E and USB ports) but any one will work.
For an Intel Core i3, i5 or i7 desktop processor, you need a motherboard using the LGA1151 socket. As with AMD there are a variety of chipsets available to suit different needs; note however that some chipsets are designed for older “Skylake” processors, and won’t work with the seventh-generation “Kaby Lake” CPUs recommended below – check before you buy.
How many cores do I need?
The truth is, it depends on what you want to do. For lightweight desktop computing, a dual-core CPU is just about fine – although four cores will help things run more smoothly when you have lots of applications or browser tabs open. For heavyweight jobs such as video editing or 3D rendering, it’s normally a case of the more cores, the better. Some CPUs can also help by using technical tricks to simulate twice as many cores as they really have; most AMD Ryzen processors have this capability, as do most Intel Core i3 and Core i7 processors.
What clock speed should I look for?
As a rule, higher is better – but advertised speeds can be deceptive, because modern CPUs dynamicallly adjust their own clock rates to suit the workload. In general, the highest “Turbo” speed is more important than the base frequency. In many cases you can overclock the processor to get whatever speeds you like – this applies to all AMD Ryzen models, and all Intel processors with a “K” suffix.
Be warned, though: to make this work, you might have to turn up the motherboard’s core voltage (“vcore”). And the faster you go, the higher the likelihood that your CPU will overheat and crash. This shouldn’t damage your computer, but it’s annoying; you can reduce the risk by investing in a high-end cooler, or even a sophisticated water-cooling system.
What about graphics?
Intel’s Core processors come with quite sophisticated built-in GPUs. They’re not powerful enough to play the latest games with maximum detail settings – you’ll need a dedicated graphics card for that – but they’re fine for a spot of Minecraft, and for watching high-definition video. If you’re looking for a cheap, simple system, that could swing it for Intel: AMD is working on a range of Ryzen-based chips with built-in graphics, but its current CPUs don’t have any built-in graphical capabilities, and require a standalone graphics card.
Anything else I need to look out for?
CPUs are complex things, and there are plenty of other technical factors that affect performance, including how much cache RAM is built into the chip and what sort of lithography process is used to make the chips. However, their impact is much less significant than overall speed and core count: if you focus on those key factors, you won’t go far wrong.
The best CPUs to buy
1. AMD Ryzen 3 1200: The best budget CPU – superb performance on a shoestring budget
Price when reviewed:£99 inc VAT
The Ryzen 3 1200 is the cheapest member of AMD’s Ryzen family, and at £99 it’s a real bargain. For the same price you can buy an Intel Core i3-7100, but that’s a dual-core CPU, while this is a true quad-core model. Just note that it lacks AMD’s simultaneous multi-threading technology, so it can only handle four threads at a time – not eight, like some more expensive models.
The Ryzen 3 1200 has a base clock of 3.1GHz with a turbo frequency of 3.4GHz and an additional 50MHz of XFR boost too. Those numbers aren’t particularly high, but you’re not stuck at those speeds: like all Ryzen chips, the 1200 can be freely overclocked. With vcores set to 1.425V, we were able to get it all the way up to 4GHz.
In our image-editing benchmark, this put the overclocked Ryzen 3 1200 very close to the performance of the Core i3-7350K – Intel’s most powerful Core i3, costing £65 more. And in our heavy multitasking video encoding test, the AMD CPU was comfortably faster than its Intel rival.
If you’re trying to put together the cheapest possible system, remember that Ryzen chips don’t have onboard graphics, so you’ll need to budget for a graphics card. And keep your expectations realistic; the Ryzen 3 1200 can’t keep up with a Core i5 processor. Even so, if you’re game for some overclocking, it’s a stunning deal – a 4GHz quad-core CPU for £99 inc VAT. You simply can’t get more bang for your buck.
Key specs - AMD Ryzen 3 1200 | |||
| Frequency | 3.1GHz | Simultaneous multithreading | No |
| Turbo frequency | 3.4GHz | Cache | 8MB L3 cache, 2MB L2 cache |
| Core | Summit Ridge / Zen | Memory controller | Dual channel DDR4, up to 2666MHz |
| Manufacturing process | 14nm | Packaging | AMD Socket AM4 |
| Number of cores | 4 x physical | Thermal design power (TDP) | 65W |
| Features | XFR, Precision Boost, FMA3, F16C, SHA, BMI / BMI1 + BMI2, AVX2, AVX, AES, SSE4a, SSE4, SSSE3, SSE3, SSE2, SSE, MMX | ||
2. Intel Core i5-7600K: An affordable, highly overclockable quad-core workhorse
Price when reviewed:£201 inc VAT
Intel’s Core i5-7600K is very similar to its flagship Core i7-7700K processor. However, while both chips have four cores, the i5 lacks Hyper-Threading, so it can only handle four tasks at once, rather than eight. The L3 cache falls from 8MB to 6MB, and clock speeds are slightly slower, with a base frequency of 3.8GHz and a turbo frequency of 4.2GHz. Since it’s unlocked, however, that’s largely irrelevant.
Indeed, we found the Core i5-7600K was a great overclocker. We reached a stonking 5.1GHz using a modest vcore of 1.38V; getting to 4.9GHz required just 1.21V. That means you should be able to hit very high speeds without having to invest in a specialist cooler.
To be clear, it’s still not quite as powerful as the Core i7: at stock speeds the Core i5-7600K is only a small step up from the last-generation Core i5-6600K. Based on our experience though, you’re likely to be able to get it to run stably at higher speeds. And on top of that, it features Intel’s new 4K video engine, which can encode and decode super-high-definition video in hardware, so playback is much smoother than on the older chip, and power consumption is lower.
In short, the i5-7600K is a great choice for a quad-core desktop – especially if you’re happy to tweak the clock speeds.
Key specs - Core i5-7600K | |||
| Frequency | 3.8GHz | Hyper-threading | No |
| Turbo frequency | 4.2GHz | Cache | 6MB L3 cache, 256KB L2 cache |
| Core | Kaby Lake | Memory controller | Dual channel DDR4, up to 2400MHz |
| Manufacturing process | 14nm | Packaging | LGA1151 |
| Number of cores | 4 x physical | Thermal design power (TDP) | 91W |
| Features | Turbo Boost 2, Virtualization (VT-x), Virtualization for Directed I/O (VT-d), VT-x with Extended Page Tables (EPT), Intel 64, Idle States, Enhanced SpeedStep, Smart Response, Intel AES | ||
3. AMD Ryzen 5 1600: A mid-price, six-core marvel
Price when reviewed:£189 inc VAT
The Ryzen 5 1600 sits right in the middle of the Ryzen range. Its clock speeds are a fair bit slower than the souped-up 1600X, with a maximum frequency of 3.65GHz compared to 4.1GHz for the X-edition CPU.
That doesn’t mean it’s a weedy chip, though. Thanks to its six physical cores, it outpaced the Core i5-7600K by sizeable margins in our Cinebench and video-encoding benchmarks. And remember that all Ryzen processors can be overclocked: we were able to push the Ryzen 5 1600 up to 3.9GHz using a vcore of 1.425V. This was enough to put it ahead of even the mighty Core i7-7700K in our Handbrake video encoding test and Cinebench.
The Ryzen CPU was a bit slower than the Intel chips in some games. The pricier Core i5, once overclocked, was 4% faster in Total War: Warhammer, and 9% ahead in Ashes of the Singularity: Escalation. This isn’t a universal rule, though: we saw no difference at all in Fallout 4.
If you’re wary of overclocking then the Ryzen 5 1600X offers better performance out of the box, but it’s £30 more expensive. If you don’t mind getting a little hands-on with core speeds, the Ryzen 5 1600 offers a stunning amount of CPU power for the money.
Key specs - AMD Ryzen 5 1600 | |||
| Frequency | 3.2GHz | Simultaneous multithreading | Yes |
| Turbo frequency | 3.6GHz (50MHz XFR) | Cache | 16MB L3 cache, 6x 512KB L2 cache |
| Core | Zen | Memory controller | Dual channel DDR4, up to 2666MHz |
| Manufacturing process | 14nm | Packaging | AMD Socket AM4 |
| Number of cores | 6 x physical (12 threads) | Thermal design power (TDP) | 65W |
| Features | Simultaneous MultiThreading, Precision Boost, Extended Frequency Range, AMD Virtualisation Technology, MMX, AMD 64, AES, Idle states | ||
4. Intel Core i7-7700K: An impressively powerful quad-core CPU for high-end roles
Price when reviewed:£291 inc VAT
The Core i7-7700K is very similar to last year’s Core i7-6700K: it’s still a quad-core, Hyper-Threaded CPU using a 14nm process. The most significant change is to the default clock speeds: the base clock has risen from 4GHz to 4.2GHz, and the turbo frequency now stands at 4.5GHz, up from 4.2GHz. This means it’s faster out of the box, but since K-series CPUs are unlocked, default speeds are largely irrelevant to overclocking enthusiasts.
If we sound unexcited, it’s only because it’s hard to improve on what was already an extremely powerful processor. No matter what you’re doing, the Core i7-7700K is faster than any other chip in Intel’s desktop line-up, leaving aside “extreme” designs like the Core i9-7900X, which costs three times as much.
If there’s a fly in the ointment, it’s Ryzen: the Core i7-7700K is still the fastest chip around for single-threaded computing, but when it comes to heavy multitasking it naturally struggles to keep up with AMD’s six-core and eight-core chips. However, our sample was a great overclocker – we managed to hit 5GHz using a vcore of just 1.36V, which goes a long way to erode the difference.
Ultimately, the Core i7-7700K is a hugely powerful chip, and the fastest mainstream Intel desktop CPU. If you rely on multi-threaded performance, however, consider what AMD has to offer before investing.
Key specs - Core i7-7700K | |||
| Frequency | 4.2GHz | Hyper-threading | Yes |
| Turbo frequency | 4.5GHz | Cache | 8MB L3 cache, 256KB L2 cache |
| Core | Kaby Lake | Memory controller | Dual channel DDR4, up to 2400MHz |
| Manufacturing process | 14nm | Packaging | LGA1151 |
| Number of cores | 4 x physical (8 threads) | Thermal design power (TDP) | 91W |
| Features | Turbo Boost 2, Hyper-Threading, Virtualization (VT-x), Virtualization for Directed I/O (VT-d), VT-x with Extended Page Tables (EPT), Intel 64, Idle States, Enhanced SpeedStep, Smart Response, Intel AES | ||
5. AMD Ryzen 7 1700: An eight-core processor that’s fantastic value for overclockers
Price when reviewed:£274 inc VAT
The Ryzen 7 1700 isn’t the top of AMD’s range: it has slower stock frequencies than the Ryzen 7 1700X and 1800X, and the lack of an “X” in its name implies that it might not overclock so well. However, it’s aggressively priced, and has twice as many cores as Intel’s (more expensive) Core i7-7700K, coupled with a super-low TDP of just 65W.
Out of the box, things might not look promising: the Ryzen 7 1700 has a relatively slow base clock of just 3GHz. As a result, it fell some way behind the Core i7 in single-threaded benchmarks, and even struggled to keep up in multi- threaded tasks, despite having eight physical cores to draw on.
However, using AMD’s Ryzen Master overclocking suite, we were easily able to tweak the Ryzen 7 1700’s clock speed right up to 4.05GHz, using a 1.425V vcore. As you’d expect, this transformed our benchmark results, allowing Ryzen to show its true power and put Intel’s best to shame.
As usual with Ryzen, the best results require on a little bit of tweaking and experimenting. But if you don’t mind that, the Ryzen 7 delivers exceptional performance coupled with remarkably low power consumption. For the price, it’s a stunning processor.
Key specs - AMD Ryzen 7 1700 | |||
| Frequency | 3GHz | Simultaneous multithreading | Yes |
| Turbo frequency | 3.7GHz | Cache | 16MB L3 cache, 4MB L2 cache |
| Core | Zen | Memory controller | Dual channel DDR4, up to 2400MHz |
| Manufacturing process | 14nm | Packaging | AMD Socket AM4 |
| Number of cores | 8 x physical (16 threads) | Thermal design power (TDP) | 65W |
| Features | Precision Boost, SMT, SMEP, AMD64, FMA3, F16C, SHA, BMI / BMI1 + BMI2, AVX2, AVX, AES, SSE4a, SSE4, SSSE3, SSE3, SSE2, SSE, MMX | ||
6. Intel Core i9-7900X: A 10-core beast of a processor – with a price to match
Price when reviewed:£989 inc VAT
Yes, this barnstorming ten-core i9-7900X is horrifically expensive – and to use it you’ll need a pricey X299 motherboard with an LGA2066 processor socket. Still, it’s still a lot cheaper than its predecessor, the £1,500 Core i7-6950X. That’s probably thanks to AMD, whose eight-core Ryzen 7 chips have seriously shaken up the market.
Interestingly, it’s not even the flagship of the new Core i9 range, but actually the cheapest member of a family that’s set to include 12, 14, 16 and 18-core CPUs. Even so, there’s a hell of a lot of power here: the Core i9-7900X comfortably beat last year’s Core i7-6950X in our heavily multi-threaded Handbrake video encoding benchmark, and left regular Core i7 processors in the dust.
And when it comes to overclocking, we were able to hit 4.6GHz with a vcore of 1.24V, providing a significant boost on top of that. Just be warned that this CPU gets hot very quickly – you’ll need a liquid cooler to hit its maximum frequencies. It’s power-hungry too, with our test system drawing a stiff 270W from the wall.
It must be noted that the 8-core Ryzen 7 1800X isn’t far behind the Core i9-7900X in terms of performance, despite costing half as much. When AMD shortly releases its new “Threadripper” CPUs with up to 16 cores, Intel’s going to have a real fight on its hands. It will also be interesting to see how the forthcoming Core i9’s bigger brothers stack up. For now, though, if you want the most powerful desktop CPU on the planet, look no further.
Key specs - Core i9-7900X | |||
| Frequency | 3.3GHz | Hyper-threading | Yes |
| Turbo frequency | 4.5GHz | Cache | 13.75MB L3 cache, 10MB L2 cache |
| Core | Skylake-X | Memory controller | Dual channel DDR4, up to 2666MHz |
| Manufacturing process | 14nm | Packaging | LGA2066 |
| Number of cores | 10 x physical (20 threads) | Thermal design power (TDP) | 140W |
| Features | Turbo Boost Technology 2, Turbo Boost Technology 3, FMA3, F16C, SHA, BMI / BMI1 + BMI2, AVX-512, AVX2, AVX, AES, SSE4a, SSE4, SSSE3, SSE3, SSE2, SSE, MMX | ||