Intel's Skylake architecture and corresponding platform represent a huge evolution in connectivity, overclocking and, ultimately, system performance. This resource should help answer any questions you have about the company's current desktop PC design.
Skylake Consumer And Business Chipsets
Since the release of Intel's Skylake-based processors, we have been working tirelessly to learn everything there is to know about the architecture and its associated platform. The information we have accumulated over a number of months, but it seems to be constantly changing, creating confusion among tech enthusiasts. And so we're aiming to clear up conflicting information and condense everything we know about the Skylake platform down into a single resource.
Intel released a total of six chipsets targeting its consumer and business customers. These platform controller hubs follow the same structure used for years to cover Intel's relevant markets. Three are consumer-oriented SKUs and three are designed for business.
Skylake Consumer Chipsets
|Intel 100 Series Consumer Chipsets|
|CPU PCIe 3.0 Config Support||1x16, 2x8 or 1x8 + 2x4||1x16||1x16|
|Recommended Customer Price||$47||$32||$26|
|Independent Display Support||3||3||2|
|Memory Channels/ DIMMs per Channel||2/2||2/2||2/1|
|CPU Overclocking Support||Yes||No||No|
|Intel Smart Sound Technology||Yes||Yes||No|
|Intel Small Business Advantage 4.0||No||Yes||No|
|Intel Small Business Basics||No||Yes||Yes|
|Intel RAID Support 0/1/5/10||Yes||Yes||No|
|Intel Smart Response Technology||Yes||Yes||No|
|Max Intel RST for PCIe||3||2||0|
|I/O Port Flexibility||Yes||Yes||No|
|Maximum HSIO Lanes||26||22||14|
|Chipset PCIe Support||20 PCIe 3.0 Lanes||16 PCIe 3.0 Lanes||6 PCIe 2.0 Lanes|
|USB Support (USB 3.0)||14 (10)||14 (8)||10 (4)|
|SATA 6Gb/s Ports||6||6||4|
At the high end, we have the enthusiast Z170 chipset. In addition to featuring RAID 0/1/5/10, multi-GPU support and offering a wide selection of connection options, it is also the only PCH officially able to overclock Skylake-based processors. Z170 is followed up by the mid-range H170, which also offers a lot of I/O connectivity and RAID 0/1/5/10 functionality, but lacks overclocking and multi-GPU support via the CPU.
H170 is often advertised as supporting multiple graphics cards, but motherboards based on it can only run a multi-GPU setup in a x16/x4 configuration. This is because the PCH doesn't allow the CPU to divide its PCIe lanes between multiple devices. A second GPU can be connected over a four-lane PCIe 3.0 link through the PCH, which may be sufficient for some GPUs, but Nvidia doesn't let you enable SLI over a x4 connection.
At the bottom of the consumer chipset stack is H110, by far the most limited PCH. Instead of using a DMI 3.0 connection between the CPU and core logic, it employs the older DMI 2.0 technology. It's basically a budget-oriented approach to supporting Skylake-based processors.
Skylake Business Chipsets
|Intel 100 Series Business Chipsets|
|CPU PCIe 3.0 Config Support||1x16, 2x8 or 1x8 + 2x4||1x16||1x16|
|Recommended Customer Price||$47||$43||$28|
|Independent Display Support||3||3||3|
|Memory Channels/ DIMMs per Channel||2/2||2/2||2/2|
|Intel SIPP Eligible||Yes||Yes||No|
|Intel vPro Technology Eligible||Yes||No||No|
|Intel Active Management Technology||Yes||No||No|
|Intel RAID Support 0/1/5/10||Yes||No||No|
|Intel Smart Response Technology||Yes||No||No|
|Max Intel RST for PCIe||3||0||0|
|Maximum HSIO Lanes||26||20||18|
|USB Support (USB 3.0)||14 (10)||14 (8)||12 (6)|
|SATA 6Gb/s Ports||6||6||6|
|Chipset PCIe Lanes||20 PCIe 3.0||10 PCIe 3.0||8 PCIe 3.0|
The business-oriented chipsets are similar to the consumer offerings, though they include a few extra features that consumers don't necessarily need.
Q170 is nearly identical to Z170, but of course lacks overclocking support. Moreover, it features Intel SIPP, vPro Technology and Active Management Technology. Q150 is nearly the same as H170 as well, except it has fewer HSIO and PCIe lanes. Plus it lacks RAID and Intel’s Small Business Basics software package. It is eligible for Intel’s SIPP technology, though.
The low-end B150 business chipset, however, does not match up well with H110. It offers more connectivity, DMI 3.0 and PCIe 3.0. Because of its budget price and specs, B150 is often used by consumers as a more feature-rich alternative to H110.
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Skylake Workstation Chipsets
Starting with the introduction of its Allendale- and Conroe-based microprocessors, Intel also made single-socket Xeon processor support available on its consumer-oriented platforms. Over the years, these Xeon CPUs became popular alternatives to Intel’s more expensive Core i7s because they have similar specs but sometimes cost less or include other useful features.
To stop desktop enthusiasts from turning to Xeons rather than Core i7s, Intel doesn't facilitate Xeon support on its Skylake-based consumer- and business-oriented platforms.
Instead, the company created two workstation-oriented hubs for its LGA 1151 interface: C232 and C236. Intel hasn’t given us all of their specs, but a representative did convey the basics. What we're missing is how many HSIO lanes are available on C232 and C236, which is an important piece of information (more on that below). So, we reached out to the motherboard OEMs and were told by one product manager that C232 has the same connectivity support as B150, while C236 is identical to Z170.
|Comparison Of C232 & C236 Chipsets|
|CPU Support||Celeron, Pentium, Core, Xeon||Celeron, Pentium, Core, Xeon|
|Recommended Customer Price||$34||$49|
|Max PCIe Lanes||8||20|
|CPU PCIe Configurations||1x16, 2x8, 1x8+2x4||1x16, 2x8, 1x8+2x4|
|USB 3.0||Up To 6||Up To 10|
|Intel Virtualization technology||No||Yes|
|Intel RST Enterprise||Yes||Yes|
|Intel Node Manager||No||Yes|
|Intel Standard Manageability||No||Yes|
|Intel Smart Response Technology||No||Yes|
|Trusted Execution Technology||Yes||Yes|
|Intel HD Audio Technology||No||No|
|Intel Small Business Advantage||No||No|
|Intel HD Graphics Support||No||No|
These chipsets are supposed to last longer and boast several advanced technologies that are not available on the desktop side. Other than that, their biggest advantages are multi-GPU and Xeon support.
Limiting LGA 1151-based Xeons to the C232 and C236 chipsets makes it more difficult for enthusiasts to build PCs using a Xeon processor, of course, as there are fewer motherboards sporting either PCH. Those that do exist are often pricier due to the validation work that goes into a more professional product.
Although a Xeon-based build can still be achieved for less money than a high-end Core i7, the delta is no longer as large. Most C236-based boards cost too much to make buying a Xeon economically viable. Falling back to C232 might save you some cash, but you'll also have far fewer features to use compared to Z170.
HSIO Lanes And Connectivity
Intel has been using a similar technology to HSIO (high-speed I/O) lanes (Flex /IO on Haswell-based chipsets) to interface between add-ins for years. Compared to its Haswell- and Broadwell-based platforms, however, Skylake is even more reliant on this technology, which sometimes makes understanding the connectivity options of each chipset more confusing.
Nearly every connection between the PCH and another device uses HSIO lanes. The only major connections that don’t are the USB 2.0 ports and the link between DMI link between the CPU and PCH. All USB 3.0 ports, SATA interfaces and PCIe slots consume at least one HSIO lane.
For example, Z170 exposes a total of 26 HSIO lanes, six of which are consumed by six permanently-enabled USB 3.0 ports. So, the chipset ends up with 20 configurable HSIO lanes that can be assigned to other devices. Each SATA port uses an HSIO lane as well, unless it's connected through a third-party controller (though that controller would need at least one lane to communicate with the PCH). As you can see in the diagram, GbE controllers and PCIe-based SSDs also consume available HSIO lanes.
The confusion happens when you hear what the chipset can support. Yes, you can do up to 10 USB 3.0 ports, eight SATA 6Gb/s ports, 20 PCIe 3.0 lanes and gigabit Ethernet. But the platform can only handle some of those I/O options simultaneously.
|Skylake Chipsets (Real) PCIe Connectivity|
|Max PCIe 3.0 Lanes||Max PCIe 3.0 Lanes |
If All USB, SATA & Single GbE In Use
|H110||6 (PCIe 2.0)||6 (PCIe 2.0)||2.0|
The biggest issue is that the maximum number of PCIe 3.0 lanes on each chipset will likely never be exposed. In order to have 20 lanes configured, which is technically possible on Z170, Q170 and C236, you would have to give up all SATA-based storage, native GbE and USB 3.0 ports beyond the six hard-wired ones.
Motherboard manufacturers make the situation more difficult to explain by launched products with more physical connections than the PCH can support at any one time. Engineers make all of the I/O functional by tying multiple devices to a single HSIO lane. Devices that share a lane cannot function simultaneously. So, often, connecting one piece of hardware disables other ports or features elsewhere. And it doesn't help that board vendors don't make this well-known. Most of the spec sheets we've seen do spell out which connections share HSIO lanes, but it's sometimes hidden in fine print somewhere at the bottom. As a result, even enthusiasts get caught buying motherboards based on their connectivity options without realizing they can't all be used together.
Memory And Bandwidth
DMI And Bandwidth
Another potential issue is the interface between the CPU and PCH. DMI 3.0 is essentially equivalent to a four-lane PCIe 3.0 link, offering roughly 4 GB/s of bi-directional bandwidth. All I/O from your USB-attached thumb drive, SATA-based SSD and gigabit Ethernet network goes through the PCH and across that interface before landing in system memory and eventually the CPU or GPU.
Using multiple devices simultaneously connected to the PCH forces them to compete for bandwidth. Intel claims that there shouldn't be as much contention now that the third-gen DMI doubles the previous generation's peak throughput, but it's still a plausible concern. That's one reason you probably wouldn't want to use a multi-GPU configuration on a chipset like H170 that won't divide the CPU's PCIe lanes between multiple graphics cards. It's also one of the reasons why Nvidia doesn't allow SLI across four-lane links.
Starting with Skylake, Intel added DDR4 support to its memory controller. But because the technology is still fairly new, the company retained support for DDR3 as well, easing adoption of its most modern platform.
Don't take that to mean any DDR3 module will work with Skylake, though. Only DDR3 operating at or below 1.35V is officially supported, and using DDR3 at higher voltage levels could damage the CPU's integrated memory controller.
Several board vendors list support for RAM operating at higher voltage levels, and you may not run into problems using RAM rated for 1.5 or 1.65V, but Intel doesn't recommend it. A lot of damage materializes slowly over time due to electromigration. As such, you'll want to carefully weigh the risks of dropping older modules into Skylake-based systems, providing you have a motherboard with DDR3 slots at all.
As it created previously, Intel has a couple of Skylake-based CPUs with unlocked clock multipliers (the K-series SKUs). These can be overclocked by simply increasing the ratio on a Z170 motherboard. The company also made changes to its PCH that again enable BCLK-based overclocking as well.
As a result, some motherboard vendors are trying to arm their platforms with the ability to overclock non-K-series CPUs, and to make some of Intel's other chipsets overclock as well. Although these capabilities would be immensely popular among enthusiasts, there are a few problems with trying to tune multiplier-locked Skylake-based CPUs.
For instance, once the BCLK of a non-K-series processor rises above its stock 100MHz, certain power-saving features, Turbo Boost and specific instructions no longer work. Thus far, this happens on all motherboards capable of overclocking non-K-series processors, regardless of chipset. The board vendors are forced to disable those features while overclocking to ensure stability. Their loss isn't debilitating, especially since power-saving features are often disabled as part of an overclock anyways. However, we know nobody likes restrictions imposed on them forcibly.
Currently, there are only two companies with motherboards capable of overclocking non-K-series CPUs. Supermicro was first on the scene, and it also has a platform that can overclock based on a chipset other than Z170. Its C7H170-M employs the H170 PCH and is built a lot like competing Z170 boards. As of this writing, the company doesn't have any other boards capable of overclocking non-K-series CPUs.
ASRock's Shifting Position
ASRock also has non-Z170 motherboards capable of overclocking non-K-series Skylake CPUs, but they've been hit by several setbacks. ASRock initially announced “Sky OC” both as a feature for Z170 boards and as a family of overclockable non-Z170 motherboards. Thus, any product with the Sky OC feature was able to overclock non-K processors, and the boards based on chipsets other than Z170 could overclock K-series CPUs using BCLK adjustments as well.
Not long after ASRock announced these boards, the company contacted Tom’s Hardware to let us know it abandoned their development under pressure from Intel. It was also forced to remove the Sky OC feature from its Z170 motherboards.
The quote went a little something like, “ASRock has decided to remove SKY OC technology from these motherboards’ feature lists since it is not compliant with Intel Skylake CPU specifications.”
We expected that to be the end of ASRock’s venture into overclocking non-K-series CPUs and overclockable non-Z170 chipsets, but then the company released its cancelled C232 Fatal1ty E3V5 Performance Gaming/OC board. It also announced its new “Hyper” family of non-Z170 motherboards able to overclock non-K-series processors using BCLK manipulation. Currently, the C232 Fatal1ty E3V5 Performance Gaming/OC is the only one of these boards available for sale online. The others may materialize in time, but it's also possible that Intel again applied pressure to stop their introduction.
Fallen Attempts At Non-K OC
Biostar tried to arm its motherboards with the ability to overclock non-K CPUs using a BIOS update for its Z170 boards. The approach was similar to the way ASRock enabled Sky OC. And like ASRock, Biostar removed the feature through another BIOS build that included new microcode from Intel.
According to a representative, “Intel regularly issues updates for our processors which our partners voluntarily incorporate into their BIOS. The latest update provided to partners includes, among other things, code that aligns with the position that we do not recommend overclocking processors that have not been designed to do so. Additionally, Intel does not warranty the operation of the processor beyond its specifications.”
Supermicro does not appear to have applied this update to its C7H170-M motherboard, but that could be just a matter of time. Technically, all of these boards are still able to overclock non-K CPUs, though to do so requires an outdated BIOS that might have other issues. This makes unsanctioned overclocking essentially dead.
Are You Looking At A Skylake Motherboard?
Intel's Skylake-based processor launch was one of the most hectic in recent history. The company's focus has changed, and the way it disseminates information isn't as thorough as it once was. Consequently, new information about the architecture and its supporting chipsets seems to trickle out slowly, whereas we were previously much better connected to the minds responsible for platform development. Several of the most recent disclosures were sponsored by motherboard OEMs exploring features and capabilities to give them an advantage over the competition.
Those board vendors may still have a few tricks up their sleeves. Overclocking non-K-series CPUs is still a hot topic, so it's possible that OEMs will continue looking for more graceful ways to achieve this. Meanwhile, we expect Intel will continue inhibiting the value-seeking tendencies of enthusiasts looking to buy something inexpensively and extract maximum performance from it. Should Intel surprise us and back off of its aggressive stance, other board vendors may try to create non-Z170 platforms with overclocking features as well. So, don't be surprised to see this story change over time as we work to keep an up-to-date reference on everything there is to know about Skylake.
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