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Skylake for desktops: New socketed processors from Core i7 to Pentium [Updated]

Intel casts a wide net with first top-to-bottom architecture refresh since 2013.

Skylake for desktops: New socketed processors from Core i7 to Pentium [Updated]
Orestis Bastounis

It's been over two years since Intel's entire lineup of socketed desktop processors got a true refresh. We got a smattering of high-end Broadwell chips this year and a small speed bump to the Haswell lineup last year, but it's been a while since system builders and desktop buyers had much to be excited about.

We've already looked at a couple of these CPUs, particularly the high-end unlocked i7-6700K. But today Intel is announcing (alongside many mobile CPUs) a more comprehensive desktop refresh that also encompasses mainstream dual- and quad-core CPUs, a few low-power options for smaller systems, and wallet-friendly chips from the Pentium line if you're trying to build a modern system on a budget. Intel tells us that all of these should be available for purchase before the end of the year.

Before we get into it, you should familiarize yourself with the features of the new 100-series chipsets, since we won't be covering that ground again in this article. You should also know that ultra-low-end Skylake Celeron chips are coming, but won't be released until early 2016.

The GPUs: No plans for eDRAM

Skylake's integrated GPUs
Broadwell GPUs EUs and peak clocks Replacement Skylake GPUs EUs and peak clocks
Intel Iris Pro 6200 (GT3e) 48 @ 1050 to 1150MHz, 128MB eDRAM Intel Iris Pro 580 (GT4e) 72 @ ???MHz, 128MB eDRAM
Intel Iris 6100 (28W GT3) 48 @ 1000 to 1100MHz Intel Iris 550 (GT3e) 48 @ 1000 to 1100MHz, 64MB eDRAM
Intel HD 6000 (15W GT3) 48 @ 950 to 1000MHz Intel Iris 540 (GT3e) 48 @ 950 to 1050MHz, 64MB eDRAM
Intel HD 5600 (GT2) 24 @ 1050MHz Intel HD 530 (GT2) 24 @ 900-1050MHz
Intel HD 5500 (GT2) 24 @ 850 to 950MHz Intel HD 520 (GT2) 24 @ 1000 to 1050MHz
Intel HD 5300 (GT2) 24 @ 800 to 850MHz Intel HD 515 (GT2) 24 @ 850 to 1000MHz
Intel HD Graphics (GT1) 12 @ 800MHz Intel HD 510 (GT1) 12 @ 950MHz

Update: Intel originally told us that the Iris 550 included 72 EUs, but that information was incorrect. Iris 550 has 48 EUs, but the forthcoming Iris Pro 580 includes 72 EUs. The rest of the article has been updated to reflect this information.

Nearly all of the CPUs we're talking about today include Intel's HD 530 GPU, a mainstream integrated GPU with 24 of Intel's execution units (EUs) and no eDRAM. Our testing of the HD 530 in the i7-6700K shows that it's consistently faster than the equivalent Intel HD 4600 GPU in the Haswell desktop chips, though the degree to which it is faster varies pretty widely. You can expect the difference to be as little as 10 percent or as much as 50 percent depending on what you're doing.

A couple of the Pentiums step down to the slower Intel HD 510 GPU, which we haven't tested firsthand. We know that it just has 12 EUs where the HD 530 has 24—compared to the Haswell "Intel HD Graphics" part it replaces we should see some gains and it ought to be fine for older games on lower settings, but don't expect miracles.

The unfortunate thing is that Intel tells us that there are no plans to make socketed Skylake CPUs with Iris or Iris Pro GPUs or eDRAM. Those of you hoping for high-end integrated graphics or a pool of eDRAM to use as L4 cache will need to hope that the company changes its mind. We haven't heard anything about soldered-on R-series CPUs for desktops and all-in-ones with Iris and eDRAM, but we'd assume those are still coming unless we hear otherwise.

K-series: High-end, unlocked

Intel

There are just two of these, and they're only going to appeal to a small group of people. When paired with one of the high-end Z170 chipsets and motherboards, the 91W Core i7-6700K and i5-6600K come multiplier unlocked for easy, Intel-supported overclocking. Having to buy top-end processors to overclock in the first place feels like it kind of defeats the purpose (some people overclock to break speed records and brag on forums, others do it to make cheap CPUs act more like expensive CPUs), but that ship sailed years ago.

The Core i7 includes Hyperthreading and 8MB of L3 cache, while the Core i5 only has 6MB and lacks Hyperthreading. Other than CPU clock speed, the two aren't otherwise drastically different from one another.

S-series: Aiming for the mainstream

Here's where you'll find the meat of the lineup—the S-series chips include 65W quad-core parts and 47W dual-core parts, and most buyers should be able to find something in here that suits their needs.

On the desktop, the lines between Core i7, i5, i3, and Pentium are fairly clear. Core i7s have four CPU cores with Hyperthreading enabled and the largest amount of L3 cache (in this case, 8MB). Core i5s give up Hyperthreading and step down to 6MB of cache, but still include four physical cores and retain Turbo Boost. Core i3 chips only have two cores, lose Turbo Boost, and step down to 4MB of L3 cache, but they keep Hyperthreading. And the dual-core Pentium chips come with 3MB of cache, lose Hyperthreading, and sometimes come with lower-end GPUs.

The Core i7 chip and the two fastest i5s support Intel's vPro business management features, if that's something you care about; otherwise the outline above pretty much sums up the lineup. The nice thing is that all of these CPUs support 2133MHz DDR4 and other platform features, making it relatively easy for system builders to go with a cheap Pentium or Core i3 now and step up to a Core i5 or i7 later without changing out any other components if they want.

T-series: Low-power desktops

Intel's T CPUs follow the same general rules as the S processors, they just come with lower 35W TDPs (this is true for both quad- and dual-core varieties). In many situations they'll perform similarly to the S-series, but the lower TDPs mean they have lower base clock speeds and throttle themselves more quickly under load to reduce their heat output. They're good choices for smaller cases like those used in mini-ITX builds, and they would also probably pair well the the "5×5" motherboards Intel unveiled at IDF this year.

There's one Core i7, three Core i5s, two Core i3s, and two Pentiums here. The Core i7 and the two fastest i5s support vPro, the lower-end Core i3-6100T only has 3MB of L3 cache instead of the normal 4MB, and the lowest-end Pentium G4400T is the only one with the Intel HD 510 GPU. Otherwise the lineup is straightforward—there's not even a significant difference in price between T-series chips and their S-series counterparts, so just pick the one that suits your needs and go from there.

Channel Ars Technica