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CPUs
We're still singing the same tune about CPUs in this Guide that we have been for some time. Dollar for dollar, and by almost every measure, we think Intel's CPUs are the ones to get if you want the best performance out of your PC. It's worth noting that AMD's motherboard partners have recently closed the feature-parity gap with modern Intel boards a bit by adding M.2 slots and USB 3.1 controllers to some of their latest AMD 970 and 990-series boards. Those changes don't help AMD FX CPUs' relatively weak single-threaded performance, power-hungriness, and reliance on older standards like PCIe 2.0 buses and DDR3 RAM, though.

You may have deduced this fact already, but Intel's latest CPU architecture is called Skylake. Chips built on this 14-nm silicon offer small-but-welcome increases in performance pretty much across the board, and from what we've seen, there aren't substantial premiums for choosing Skylake-compatible motherboards or memory any longer. Skylake's platform improvements are also welcome: the highest-end Z170 chipset offers more PCI Express lanes for next-generation storage and high-speed I/O ports than Intel's 9-series boards. Given these advantages, we'd generally recommend building around a Skylake processor if possible.

While we're primarily looking at Skylake parts in this guide, Intel's Broadwell Core i7-5775C still deserves a mention, too. This CPU is unique because of its 128MB of eDRAM, a resource that the i7-5775C can use as a large last-level cache. In our testing, we found that the 5775C appears to have a natural advantage in producing low frame times in games. This CPU is a bit of an odd bird, though. It relies on the older Z97 platform and DDR3 RAM, and its high cost—about $20 more than Intel's own Core i7-6700K—makes it a hard sell unless you're serious about getting the lowest frame times around or want the chip's powerful integrated graphics.

Despite our preference for Intel CPUs, AMD’s Athlon X4 880K is getting a home in our budget recommendations. This $95 quad-core CPU is basically a high-end Godavari APU with its onboard graphics disabled.  While the 880K won’t be able to match our favorite Intel Core i3-6100 in single-threaded workloads, it ships with a high-quality stock cooler and an unlocked multiplier. That means builders on a budget might be able to close the gap with the Core i3-6100 a bit. We've tested AMD’s Wraith cooler, a fancier version of the one that ships with the X4 880K, and we've found that it offers performance similar to some smaller aftermarket heatsinks. Not bad for something that comes in the box.

In our last guide, we discussed the budding possibility of overclocking non-K series Intel processors using an unofficial BCLK workaround on some ASRock motherboards. Intel has since put the kibosh on this method, leaving those who want to take advantage of this workaround to rely on out-of-date motherboard firmware or specific boards that offer external base-clock generators. We've played with this unsupported overclocking method a bit, and we've found that it comes with some tradeoffs like garbled system-monitoring data and neutered AVX performance in workloads that care about it. Unless you're willing to live with what is essentially a hack, we don't think BCLK overclocking is worth it.

Budget

Product Price Notable needs
AMD Athlon X4 880K $95.00 AMD Socket FM2+ motherboard
Intel Core i3-6100 $124.99 Intel LGA1151 motherboard

In this price range, we think Intel’s Core i3-6100 is a great buy. Its healthy 3.7GHz clock speed should be brisk enough for most, and its Hyper-Threading support can boost performance in multithreaded tasks. It’ll also appear as a quad-core CPU to games that require one. This Core i3 is a good choice for non-gamers, too, since it has basic integrated graphics. For $125, it's hard to find anything to complain about with this chip.

For those who want to tinker with clock speeds on a budget—or for folks whose budgets just don't stretch to the Core i3-6100—AMD’s Athlon X4 880K gets a conditional nod from us. Since the X4 880K is a quad-core CPU, it should also work with most modern games without a hitch. The 880K won't be as fast as the Core i3-6100 in single-threaded workloads, though, and overclocking it probably won't close the gap that much. Still, AMD's beefy stock cooler should allow budget builders to turn up the clocks without spending extra for an aftermarket cooler, and that could be an attractive value proposition for an entry-level system.

Sweet spot

Product Price Notable needs
Intel Core i5-6500 $204.99 Intel LGA1151 motherboard
Intel Core i5-6600K $244.99 Intel LGA1151 motherboard, Z170 chipset for overclocking,
aftermarket CPU cooler
Intel Core i7-6700K $359.99

Moving up to our sweet-spot picks gets builders into Intel’s quad-core CPUs. If you don’t want to get into overclocking, the Core i5-6500 looks like the Goldilocks chip in this price range. For about $205, the i5-6500 gives us 3.2GHz base and 3.6GHz turbo clocks in a miserly 65W thermal envelope. The Core i5-6500 is also a great CPU for a VR-ready machine. As a warning, we aren’t as enamored of the Core i5-6400. Though it sells for $15 less than the i5-6500, the i5-6400 pays for it with a big drop in clock speeds. We don't think the step down to 2.7GHz base and 3.3GHz Turbo speeds is worth the savings.

The logical step up from the Core i5-6500 is Intel’s Core i5-6600K. This part gives us four cores running at 3.5GHz base and 3.9GHz Turbo speeds, along with an unlocked multiplier that gives overclockers free rein. From there, the beastly Core i7-6700K adds Hyper-Threading and turns the clocks all the way up to 4GHz base and 4.2GHz Turbo speeds. Overclockers are free to explore the i7-6700K's upper limits, too.

Since Intel doesn't include a stock cooler with its K-series CPUs any longer, be sure to grab an aftermarket cooler from our selections later in this guide if you're building with a Core i5-6600K or a Core i7-6700K—and make sure it's a beefy one if you're choosing the i7-6700K. Our experience with that chip has shown that it's quite the challenge to cool, even for large tower heatsinks.

High end

Product Price Notable needs
Intel Core i7-5820K $389.99 LGA2011-v3 motherboard,
quad-channel DDR4 memory kit,
discrete graphics, aftermarket cooler
Intel Core i7-5930K $579.99

If the Z170 platform doesn't offer enough PCIe lanes or memory bandwidth for your needs, Intel's "Extreme" CPUs and X99 motherboards are the next step up for desktop PCs. It's a bit of an awkward time to be building an X99 system, though. Intel just released its Broadwell-EP Xeon CPUs, and we more or less know that a lineup of Broadwell-E desktop parts will be following those chips at some point. Even so, given that Intel's motherboard partners are already boasting that their products will be compatible with these future CPUs after a firmware update, there isn't a whole lot of risk buying an X99 mobo right now.

Even if they will be compatible with future CPUs, today's X99 motherboards seem to be getting a little long in the tooth. It's hard to find X99 motherboards with the increasingly popular USB 3.1 Type-C port, for example. We only know of one motherboard with a USB 3.1 Type-C port that doubles as a Thunderbolt 3 connector, and Thunderbolt 3 support seems like it would be nice to have in a high-end system. It's possible we'll get some updated X99 boards once Broadwell-E CPUs arrive, but those parts could be a ways off.

For now, Intel's Core i7-5960X is still one of the most powerful CPUs you can put in a desktop motherboard. This monster is based on Haswell-E silicon with eight cores, 16 threads, 20MB of L3 cache, a quad-channel DDR4 memory controller, and 40 PCI Express Gen3 lanes built right into the CPU die. This is the desktop cousin of Haswell-EP, Intel's dual-socket Xeon server processor, and it performs accordingly—with an unlocked upper multiplier to boot.

Too bad it still costs just over a thousand bucks.

For almost half the price, the Core i7-5930K serves up much of the same Haswell-E goodness. Yes, the cheaper chip has "only" six cores, 12 threads, and 15MB of L3 cache, but that still gives it a big leg up over Intel's lesser quad-core parts. The i7-5930K also has higher stock clock speeds than the i7-5960X, which might translate into even better performance than the thousand-dollar beast in many workloads. Finally, because the i7-5930K is fully unlocked, you may be able to push its performance even further by overclocking.

If you can't swallow the Core i7-5930K's cost but still want six Haswell cores in your system, we conditionally recommend the Core i7-5820K. This chip has 12 of its PCIe lanes lopped off, for a total of 28. We think Intel's decision to cripple this processor in this fashion is unfortunate, because it removes one of the key advantages of "extreme" processors on the X99 platform. Many folks who build systems with these CPUs will want 16 lanes going to two different PCIe x16 slots for multi-GPU configs. With a 5820K installed, though, an X99 system can't deliver. It effectively has no more PCIe bandwidth for SLI and CrossFire than a quad-core Skylake chip based on the much more affordable Z170 platform.

If you're not using a lot of PCIe expansion cards, this limitation may not matter, but it's something to note. The i7-5820K is still unlocked for easy overclocking, and its $390 price tag is reasonable for what it offers.