Best gaming CPUs under £200 / $250: Intel Core i5 6500/6600K

Both the Core i5 6500 and the Core i5 6600K are capable of handing in some truly remarkable gaming performance and we feel confident in recommending them for use with virtually any graphics hardware you care to pair with them.

On the face of it, there's not much to separate the two. They are based on exactly the same slice of silicon, they just run at different speeds and are priced accordingly. In heavy quad-core workloads (ie virtually all games), the cheaper Core i5 6500 operates at 3.2GHz, while the i5 6600K hits 3.5GHz. However, the latter can run at much higher speeds via overclocking - requiring a higher-end motherboard using the Z170 chipset.

Unofficially, the locked i5 6500 is also overclockable - as you can read in our full review - though Intel is working on new updates that lock out the functionality. The firm can't force you to update, so retaining that feature is simply a case of finding a Z170 board that hasn't had Intel's latest update applied.

Whether you're overclocking an i5 6500 or an i5 6600K, the results are explosive. In fact, if you have time, check out this analysis of the Core i7 3770K - still a respectable CPU even now. In that video, we compare an overclocked Skylake i5 and find that it's capable of much better performance, even paired with a mainstream graphics card like the GeForce GTX 970. But even running at stock speeds, these quad-core processors produce superb results on the vast majority of games, and if 60fps gameplay is your aim, both are highly viable contenders.

Given the choice between the two, the K processor is the one to get - it has more overclocking options, and they're officially sanctioned too. Also, in the UK at least, Core i5 prices can fluctuate quite substantially - the i5 6600K is pretty static at around £200, but the i5 6500 varies between £150 to £175. At the base end of that scale, it offers superb value, but at £175, its value proposition diminishes when the more powerful 6600K is just £25 more.

Core i5 6500 Skylake Review: Gaming Performance, Overclocking and More

Order our recommended i5 processors from Amazon with free shipping:

• Intel Core i5 6500
• Intel Core i5 6600K

So what makes the Skylake Core i5 processor a more viable proposition than the last-gen Haswell chips, and where does AMD fit into the equation? Well, the bottom line here is pretty simple - clock for clock, Skylake offers architectural advantages over last year's processor, but it also offers access to DDR4, which has a higher range of memory bandwidth. As you'll discover below, Intel processor performance scales in line with RAM bandwidth in CPU-bound gaming scenarios. In effect, it increases your lowest frame-rates - which are often caused by the main processor, rather than the graphics card.

However - you will need a Z170-based motherboard in order to access memory bandwidth above the baseline, rather lacklustre 2133MHz. On top of that, Z170 is required for processor overclocking too. While there are some arguments for opting for a budget-orientated board for use with an i3 processor, there's little discussion on the matter once you migrate to an i5. To get best processor performance, and by extension, to best future-proof your system, access to CPU overclocking and higher bandwidth memory is a must - and right now, that means Z170.

First up, let's take a look at the Core i5 6500's performance level, here tested in concert with Nvidia's ultra-fast Titan X, running overclocked at 1080p resolution. As always, the idea here is to remove the GPU as a system bottleneck - as much as we can - and to make CPU and RAM the primary limiting factors in the system. The success of this varies on a per-game basis, but the trends become clear - the more memory bandwidth available to your system, the faster the CPU can process the game logic. Between 2133MHz to 3200MHz DDR4, we can see anything up to a 14fps difference - and that's before we've even factored in overclocking.

The results here also include i5 6500 overclocking, with the chip raised from its 3.2GHz base clock to a mammoth 4.51GHz - right up there with the results possible from the 6600K. You'll note that in many cases, the lion's share of the performance uplift can be achieved with faster RAM alone. Some games prefer more memory bandwidth, while others thrives in faster CPU clocks. It emphasises that faster memory can make a difference, even if you Intel succeeds in completely locking out CPU overclocking on locked chips.

Core i5 6500 CPU vs RAM Overclocking Gaming Benchmarks

Next up, we're going to compare the Core i5 6500 and i5 6600K, both overclocked and paired with 2666MHz DDR4. And on top of that, we'll factor in the next logical upgrade - the much more expensive Core i7 6700K, which we'll cover in more depth on the next page. While we would have liked to have included an AMD alternative, the fact is that Intel are way ahead of the game here - we will need to see AMD's upcoming Zen processors (due later this year) to see if the red team are indeed back in the game. For now, in the mainstream enthusiast sector, Intel is the only viable option.

The results in the benchmark table below are rather interesting - for starters, the unofficial Core i5 6500 overclock turns out to be not quite as potent as the 'official' overclocking route offered by the Core i5 6600K, but the differential varies on a game by game basis and let's be frank, there's not a huge amount in it in pure percentage terms. With overclocking in play, the close grouping of the results shows that you're getting something pretty close to class-leading performance at a pretty decent price. It may also suggest that using Titan X to eliminate the GPU as the bottleneck becomes less effective as CPU performance scales up.

In truth, the i7 generally hands in more consistent frame-rates and less stutter in really extreme, taxing gameplay scenarios, but unless you make a habit of playing Crysis 3, the chances of encountering these situations is fairly remote. The results emphasise that an overclockable i5 an extremely potent piece of gaming kit.

Core i5 6500 4.5GHz BCLK Overclock vs i5 6600K/i7 6700K Gaming Benchmarks

The sheer power afforded by an overclocked Core i5 6600K is all the more compelling bearing in mind that we consider the Core i7 6700K as the current standard bearer in terms of cutting-edge gaming performance - and as you'll discover on the next page, Intel produces six and eight-core chips, but remarkably they aren't quite as powerful as the 6700K when it comes to gaming applications.

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