Best CPUs Under £400

1. AMD Ryzen 5 3600 Processor (6 Cores/12Threads, 65W DTP, AM4 Socket, 35 MB Cache, up to 4.1 GHz Max Boost frequency, Wraith stealth cooler)

The Ryzen 5 3600 has been around long enough that calling it a classic feels fair. Six cores, 12 threads, a 35MB cache, and a 4.1GHz max boost on the mature Zen 2 architecture. It is not the fastest chip on this list, but for the money it remains one of the most sensible all-round purchases you can make in a budget build.

What makes it stand out in a roundup of the best CPUs under £400 is the combination of platform maturity and outright affordability. AM4 motherboards are cheap and plentiful. The Wraith Stealth cooler is included, so you are not adding another £30 to £50 to your build cost. And 12 threads means it handles everyday multitasking, light video editing, and gaming without breaking a sweat.

Look, it is not going to compete with Zen 3 or Zen 4 chips in raw benchmarks. Single-core performance lags behind the 5600X noticeably, and if you are gaming at high frame rates you will feel that gap. But for a first build, a home office machine, or someone who just wants a capable processor without overthinking it, the 3600 is still proper decent value. Real owners consistently praise its reliability and the fact that it just works out of the box with almost any AM4 board.

The 65W TDP also means it runs cool and quiet under the Wraith Stealth, which is a bonus if your case airflow is not exactly optimised.

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2. AMD Ryzen 5 5600X Processor (6 Cores/12Threads, 65W TDP, AM4 Socket, 35MB Cache, up to 4.6 GHz Max Boost, Wraith Stealth Cooler)

Here is the thing: the Ryzen 5 5600X is arguably the best gaming CPU value on this entire list. Zen 3 brought a significant IPC (instructions per clock) improvement over Zen 2, and you feel it. The 4.6GHz max boost combined with that architectural uplift means gaming performance is genuinely strong, comfortably ahead of the 3600 and competitive with much newer chips.

For anyone building a gaming PC as part of the best CPUs under £400 search, this is where most people should start. It pairs brilliantly with a mid-range GPU, keeps power consumption sensible at 65W, and the included Wraith Stealth cooler means you are ready to go without extra spending. AM4 boards are cheap, which keeps your total build cost down.

The 35MB cache is the same as the 3600, but the Zen 3 architecture uses it more efficiently. Productivity tasks like code compilation, light video editing, and streaming while gaming all feel noticeably smoother than on the older chip. Real-world owner feedback is overwhelmingly positive, with most people noting it runs well within thermal limits even on the stock cooler.

The only honest caveat is platform longevity. AM4 is not going to get many more new CPU releases, so if you plan to upgrade again in two or three years, you might hit a ceiling. But for the price right now, it is hard to argue against.

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3. AMD Ryzen 5 4500 Processor (6 Cores/12 Threads, 65W DTP, AM4 Socket, 11 MB Cache, Up to 4.1 GHz Max Boost, wraith stealth cooler)

The Ryzen 5 4500 sits in an awkward spot. Six cores and 12 threads at a competitive price sounds great on paper, but the 11MB cache is notably smaller than the 3600's 35MB, and Zen 2 architecture means single-core performance is similar to the older chip. It is not a bad processor, but it requires a bit of honest context.

For a first-time builder who wants a capable everyday machine without spending too much, it works fine. Web browsing, office tasks, video calls, and light gaming are all within its comfort zone. The Wraith Stealth cooler is included, which is always welcome at this price point. And AM4 compatibility means you have a wide choice of affordable motherboards.

Where it falls short is in gaming and heavier workloads. The limited cache hurts in CPU-sensitive games, and the 5600X is usually close enough in price that it makes more sense for most buyers. If the 4500 is significantly cheaper at the time you are shopping, it is a reasonable pick. But do not choose it over the 5600X just to save £10 to £15.

For absolute beginners who just want something that works and are not planning to push the system hard, it is a solid, uncomplicated starting point.

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4. AMD Ryzen 5 7600 Processor (radeon graphics integrated, 6 cores/12 threads, 65W TDP, AM5 Socket, 38MB cache, up to 5.1 GHz max boost, Wraith Stealth Cooler)

The Ryzen 5 7600 is where things get interesting for anyone thinking beyond the next couple of years. AM5 is AMD's current platform, and they have committed to supporting it well into the future. That means buying a 7600 today gives you a realistic upgrade path to faster chips later without changing your motherboard.

The 5.1GHz max boost is a proper step up from AM4 chips, and Zen 4 architecture delivers noticeably better single-core performance than Zen 3. It also includes integrated Radeon graphics, which is genuinely useful. You can get a system up and running without a dedicated GPU, then add one later when your budget allows. That flexibility is worth real money for budget builders.

The 38MB cache is solid, and the 65W TDP keeps things cool. The Wraith Stealth cooler is included, which is a nice touch given that some newer chips in this roundup skip it entirely. The main cost consideration is the AM5 motherboard, which will add more to your build than an AM4 board. Budget B650 boards are available around £100 to £120, so factor that in.

For anyone who wants a future-proof foundation and does not mind spending a little more on the platform, the 7600 is a smart pick among the best CPUs under £400.

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5. AMD RYZEN ™ 7 9800X 3D Desktop Processor (8-core/16-thread, 104MB cache, up to 5.2 GHz max boost)

If gaming performance is your priority and you have the budget, the Ryzen 7 9800X 3D is the answer. Full stop. The 3D V-Cache technology stacks an additional layer of L3 cache directly on the chip, bringing the total to a massive 104MB. In gaming, where cache latency and size directly affect frame rates, this makes a measurable, real-world difference.

Benchmarks consistently show the 9800X 3D leading the field in gaming frame rates, often by a significant margin over non-3D chips. It is the best gaming CPU AMD makes right now, and at under £400 it sits at the very top of this roundup's budget. Eight cores and 16 threads mean it is no slouch in productivity either, though the 3D V-Cache design does limit overclocking potential compared to the standard 9700X.

The 5.2GHz max boost sounds lower than the 9700X's 5.5GHz, but in practice the cache advantage more than compensates in gaming workloads. Power draw is higher at 104W, so a decent cooler is essential. No cooler is included, which is worth noting when budgeting.

For anyone building a dedicated gaming rig and wants the best chip available in the best CPUs under £400 category, this is it. Just make sure your total build budget accounts for an AM5 board and a proper cooler.

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6. AMD Ryzen 5 9600X Processor (radeon graphics included, 6 Cores/12 Threads, 65W TDP, Socket AM5, Cache 38MB, up to 5.4 GHz max boost Frequency, no cooler)

The Ryzen 5 9600X brings Zen 5 architecture to a six-core chip, and the result is genuinely impressive. A 5.4GHz max boost is fast for a 65W processor, and the Zen 5 IPC improvements over Zen 4 are real, if not dramatic. For gaming and everyday productivity, it punches above its core count.

Integrated Radeon graphics are included, which gives you display output without a dedicated GPU. Useful for getting a build running before a GPU arrives. The 38MB cache is competitive, and the AM5 platform means you have upgrade options down the line.

The honest frustration here is the missing cooler. At this price, bundling a Wraith Stealth would cost AMD very little and would make the overall package much more appealing. As it stands, you need to add a cooler to your budget. A decent budget option like a DeepCool AK400 or similar will add around £25 to £35 to your costs. Factor that in when comparing it against the 7600, which does include a cooler.

Still, if you want the latest Zen 5 architecture in a six-core package and are comfortable sourcing a cooler separately, the 9600X is a strong performer among the best CPUs under £400.

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7. AMD Ryzen 5 5600GT processor (integrated Radeon Graphics, 6 cores/12 threads, 65W DTP, AM4 Socket, Cache 19MB, up to 4,6Ghz max boost, with wraith stealth cooler)

The Ryzen 5 5600GT is a bit of a hidden gem. It combines Zen 3 CPU performance with integrated Radeon graphics on the AM4 platform, which is a combination that did not exist for a long time. If you want a capable everyday and light gaming machine without buying a dedicated GPU, this is the best AM4 option for it.

The integrated graphics are more capable than the basic display outputs on non-APU chips, handling light gaming and media tasks without issue. Think older titles, esports games, and casual play rather than demanding AAA games at high settings. For a home office machine that doubles as a light gaming rig, it is a genuinely smart pick.

The 4.6GHz boost and Zen 3 architecture mean CPU performance is solid. The 19MB cache is lower than the standard 5600X, which costs a little in gaming performance, but the iGPU advantage more than compensates for most use cases. The Wraith Stealth cooler is included, which keeps total build costs down.

It is a niche product, but for the right buyer, it is exactly right. If you are building a compact system, a media PC, or a budget gaming machine where a GPU is not in the immediate budget, the 5600GT earns its place in any best CPUs under £400 shortlist.

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8. AMD Ryzen 7 9700X Processor (8 Cores/16 Threads) 65W DTP, AM5 socket, 40MB Cache, Up to 5.5 GHz max boost frequency, no cooler

Eight Zen 5 cores at 65W is a remarkable engineering achievement, and the Ryzen 7 9700X is the chip that proves it. AMD managed to fit eight high-performance cores into a 65W envelope, which means it runs cool, quiet, and efficient without sacrificing meaningful performance. The 5.5GHz max boost is the highest of any non-3D chip in this roundup.

For productivity workloads, the 9700X is the best all-round chip here below the 9800X 3D. Video editing, code compilation, streaming, and heavy multitasking all benefit from those extra two cores over the six-core options. And because it runs at 65W, you do not need a beefy cooler. A mid-range air cooler handles it comfortably.

Gaming performance is strong but not quite at the 9800X 3D's level, which is expected given the lack of 3D V-Cache. For most games, the difference is small. For cache-sensitive titles, it is more noticeable. But if you split your time between gaming and productivity, the 9700X is arguably the better balanced chip.

The missing cooler is the same frustration as the 9600X. Budget for one. But the overall package, eight Zen 5 cores, 5.5GHz boost, 65W TDP, and AM5 longevity, makes it one of the most complete processors in this entire best CPUs under £400 roundup.

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9. AMD Ryzensets 9 9900X Processor (radeon graphics integrated, 12 Cores/24 Threads, 120W DTP, AM5 Socket, 76MB Cache, Up to 5.6 GHz max boost frequency, No Cooler)

Twelve cores and 24 threads of Zen 5 at under £400 is genuinely impressive, and the Ryzen 9 9900X is the chip for anyone whose workload involves serious multitasking. Video rendering, 3D modelling, large code compilations, and running multiple demanding applications simultaneously are where this chip separates itself from everything else on this list.

The 5.6GHz max boost is the highest here, and the 76MB cache is substantial. Integrated Radeon graphics are included, which is a nice touch at this tier. The 120W TDP is the honest trade-off. You will need a proper cooler, and your power supply needs to be up to the task. No cooler is included, so budget accordingly.

For gaming, it is strong but not the best pick here. The 9800X 3D's 3D V-Cache gives it a clear gaming lead despite having fewer cores. So if gaming is your primary use, the 9900X is not the right tool. But for content creators, developers, and power users who need raw multithreaded muscle, it is the most capable chip in this best CPUs under £400 roundup.

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10. AMD Ryzensets 5 8600G processor (integrated Radeon Graphics,Ryzensets AI, 6 cores/12 threads, 65W TDP, AM5 Socket, Cache 22MB, up to 5,0Ghz max booth, with wraith stealth cooler)

The Ryzen 5 8600G is the best APU option on AM5. If you want to game without a dedicated graphics card and you want the AM5 platform's longevity, this is your chip. The integrated Radeon 760M graphics are a meaningful step up from the basic iGPU options on standard Ryzen chips, capable of handling esports titles and older games at 1080p with reasonable settings.

Six Zen 4 cores, a 5.0GHz boost, and 22MB cache give you solid CPU performance for everyday tasks and gaming. The Wraith Stealth cooler is included, which is a genuine bonus on AM5 where many chips ship without one. The 65W TDP keeps things manageable thermally.

The honest limitation is that the integrated graphics, while better than most iGPUs, are still not a replacement for a dedicated GPU in demanding titles. Think of it as a capable stopgap rather than a permanent solution for gaming. When you eventually add a discrete GPU, the 8600G's CPU performance will keep up without bottlenecking a mid-range card.

For anyone building a compact PC, an HTPC, or a budget gaming machine on AM5 without an immediate GPU budget, the 8600G is the smartest pick in this category.

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11. Noctua NM-AM5/4-MP83 chromax.black,SecuFirm2 Mounting-Kit for AMD AM5 & AM4 (Black)

This one is a bit different. The Noctua NM-AM5/4-MP83 is not a CPU, it is a mounting kit for Noctua coolers that lets you use older Noctua hardware on AM5 and AM4 sockets. If you already own a Noctua cooler from a previous build, this is the accessory that makes it compatible with your new chip.

Given that several chips in this best CPUs under £400 roundup ship without a cooler (the 9600X, 9700X, and 9900X), this is genuinely useful. Noctua coolers are among the best air coolers available, and reusing one rather than buying new saves real money. The chromax.black finish keeps things looking tidy in a dark-themed build.

Installation is straightforward if you are comfortable with PC building. Noctua's SecuFirm2 mounting system is well regarded for its security and ease of use. At under £10, it is one of the best value purchases you can make alongside a new CPU if you have a compatible Noctua cooler sitting in a drawer.

It is not for everyone, but for the right buyer it is an easy recommendation.

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12. AMD Ryzensets 3 3200G processor (Radeon Vega 8 integrated GPU, 4 cores/4 threads, 65W TDP, AM4 socket, 6MB Cache, up to 4.0 Ghz max boost frequency, wraith stealth cooler)

The Ryzen 3 3200G is the most affordable chip in this roundup and the only one that comes in under £100. Four cores, four threads, Vega 8 integrated graphics, and a Wraith Stealth cooler. It is not going to win any performance awards in 2026, but for what it is, it does the job.

The Vega 8 iGPU is capable enough for basic gaming, older titles, and casual play. Think Minecraft, older indie games, and light esports rather than anything demanding. For everyday computing, web browsing, video streaming, office work, and video calls, it is perfectly fine. It is a chip that just gets on with it without fuss.

The honest limitations are real. Four cores with no hyperthreading (no SMT) means it struggles with heavier multitasking. The 6MB cache is tight. And Zen+ architecture is two generations behind Zen 3. If your budget stretches even a little further, the 5600GT or 5600X will serve you much better.

But as a first PC chip, a budget home office processor, or a stopgap while saving for something better, the 3200G earns its place as the best under £100 option in this best CPUs under £400 roundup. The included cooler and integrated graphics mean your total build cost stays genuinely low.

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