Intel Z170 “Skylake” i7-6700K PC Build

Late last year (2015), I finally built a new custom PC for sims and gaming based on the latest Intel Z170 chipset and the Intel “Skylake” series i7 processor. The new machine is intended to be cutting-edge now, and should remain upgradeable and provide excellent performance for the next five years or more. There’s been a lot going on with it — not only was I creating a custom build based on some very new parts, but Windows 10 was also new on the scene, so there was much to do in the way of “dialing in” the new system. What follows is the full-step-by step of the hardware assembly. If you’ve never built a custom PC, or if you have and are just curious, read on.

We’ll start with the obligatory beauty shot of all the boxes. This pile of odds n’ ends is going to come together into a complete PC…

It starts with the venerable Antec 900 case. Now on its third revision to include USB 3 ports on the front panel, this case isn’t cutting-edge any longer. It doesn’t have tool-less brackets for hard drives. Cable management facilities are minimal, and while it’s not small as mid-towers go, it’s still cramped inside to work on. But, it has excellent airflow capability while still remaining quiet, due in large part to the 200mm fan on the top. There’s a reason why it has close to 5000 all-positive reviews on Newegg — it’s still a favorite with experienced system builders.

Now, if you spotted the Corsair H80i V2 water cooler in the picture, you might be wondering why I’m using a high-airflow case (If not the original high-airflow case) for a water-cooled system. Why not use one of the more modern cases designed to muffle noise that have built-in mounts for larger water coolers? I decided against those designs because to my eye, their airflow was limited unless the case fans were running at higher speeds — which defeats the purpose of a quiet case design. My design idea was to maximize airflow so that the fans don’t have to run fast unless the system is really running flat-out. Remember — even a water cooler needs airflow to exchange heat across the radiator. Since the Skylake processor family is designed to be more thermally efficient, my plan is to use a relatively smaller radiator in an efficient airflow design. We’ll see how that comes together in the build and how it works out.

First off, the case is prepared for the rest of the build. And right from the start, I’m doing something unusual. Here’s the case as it comes with the wiring moved aside. Nothing fancy — even a bit outdated compared to the newer, slick case designs — but functional.

Up in the back of the case we have the usual exhaust fan. Normally, this fan pulls hot air out of the case from the CPU heatsink and fan. But this case also has a giant 200mm fan up in the top which can move far more air while running at a much slower (and quieter) speed. So we’re going to assign that big top fan the heat exhaust duty, and we’re going to remove the back 120mm fan from the case. We’ll see how that fan location gets used in a little while.

You can’t see them in the photos, but there are two more identical 120mm fans in the front panel of the case. The one I removed will be re-installed in another location later.

It’s time to prepare the motherboard. Here’s the board, fresh out of the box.

This is the Maximus VIII Hero board from ASUS. It’s a premium enthusiast-grade board designed for overclocking and high performance. As such, it’s actually ASUS’ “value-priced” enthusiast ATX-size board. There are more expensive models above it, but this one has all the core features necessary for building an extremely high-performance 24/7 PC. (Note: Since this build, ASUS has added the “Maximus VIII Hero Alpha” which is the same board with additional LED lighting capability and LED headers on the board. The rest of its specs are identical, so it’s up to you if extra lighting is worth a little extra cost or not.)

Before installing the motherboard in the case, I prefer to install the CPU and memory on the board first. I can work with the board clear of obstructions and fully supported on the bench.

ASUS and other motherboard manufacturers are now including a plastic CPU insertion tool. While some self-proclaimed “experts” are calling these useless marketing add-ons to appeal to novice builders, I disagree. There’s some good engineering sense behind it. While it’s not hard to correctly place the CPU in the socket with care by hand, Intel has been recommending and selling CPU insertion tools for use with their server CPUs for some time now. Millions of dollars of research and development money isn’t likely to be wrong. Also, the 14nm Skylake CPU is built on thinner substrate — the circuit board material that the actual chip is soldered to. The insertion tool adds some thickness and reinforcement around the edges of the substrate when it’s snapped on. Given the early reports of problems with the edges of the substrate being easier to damage than previous CPU designs, I opted to use the CPU insertion tool/spacer.

As you can see in the photos above, the CPU and the insertion tool/spacer become a single unit once the tool is snapped onto the CPU. My recommendation is to protect the contacts on the CPU while attaching the tool — which is easier said than done, since you have to press the CPU and tool together. My solution is to use a paper coffee filter between your fingers and the CPU.

Next, unlatch the CPU retainer lever and raise the retainer. Leave the plastic cover attached. Place the CPU on the socket; the installation tool will align it perfectly over the delicate pins in the socket.

Lower the retainer onto the CPU, letting it settle by its own weight and check that it’s flat atop the CPU before latching the retainer lever. At this point, the plastic cover is still attached to the retainer, and that’s OK.

Press the retainer lever down firmly and under the latch tab. It will be stiff, but it’s designed to be. In the process, the plastic socket cover will unsnap and pop off by itself. (Leaving the cover on adds a light bit of resistance that prevents any chance of the CPU “creeping” in the socket. That, plus using the insertion/spacer tool will guarantee that the CPU is correctly positioned when the retainer is latched down.)

Time to move on to installing the memory. To go with the overclock-capable I7 CPU, I’m installing 16GB of DDR-4 memory running at 3GHz. In researching the effects of overclocking DDR-4, I found that 3.2GHz is about the maximum speed that offers any noticeable performance improvement. But, the difference between 3.0GHz and 3.2GHz performance is negligible. While overclocking memory generally needs a DRAM voltage increase, 3.2GHz memory requires a significant jump for a tiny performance increase compared to 3.0GHz. I decided that 3.0GHz would provide the best performance gain while putting less stress on the system (and producing less heat) at the best price.

Unlike the common design with pivoting latches at both ends of the memory slot, ASUS uses a single-ended design to make memory installation easier — once you get the hang of it. The bottom edge of the module is inserted first and lines up with the fixed retainer, then the module is pressed into place and the pivoting top latch will close and lock. I find it’s easier to do this when the motherboard is on the workbench, because the cables running near the top of the motherboard can get in the way once it’s installed. Nevertheless, it’s easier to deal with checking for one latch per module to be properly seated than it is for two on each, so the design has its merits.

It’s important to note that on this board, the memory modules not only are to be installed in color-coded alternating slots, they are installed beginning in the second pair, furthest away from the CPU. The color coding is subtle — dark gray and light gray. The picture above shows it clearly.

I opted for 16GB spread across two 8GB modules. This arrangement will have the same to marginally less latency that spreading the same amount of memory across four modules. Also, at overclock speeds and voltage, it’s easier to keep two modules synced rather than four.

Next, the motherboard I/O connector shield is pressed into its space on the back of the case. Notice the ground tab indicated by the red arrow in the picture below. It will probably be bent too far across the opening for the USB 3.1 port. Gently bend it back so that it’s pointing into the case at about 80 degrees or so — slightly less than a right angle. It needs to press firmly against the metal shield around the USB jack, but there needs to be enough clearance that the connector’s housing will slip under the tab as the motherboard is installed. If the tab is bent too flat, it will be driven into the USB port, which can damage the connector. Worse, if gets jammed in the jack and the system is powered up, it may short the connector’s wiring, causing the network interface to fail. This is something to check for on any system build, not just this one. Ground tabs like this are typical on the connector shields, and unless they’re properly positioned and checked when the motherboard is installed, connectors and components can be damaged.

The motherboard is installed next. Make sure that the standoffs are installed in the motherboard tray so that they match up to all the screw holes. Test-fit first!

Many builders use a magnetic screwdriver to slip the rather small screws into place to fasten the motherboard. While it’s true that there’s no danger of damage from a magnetic screwdriver bit, I’m more concerned about electrostatic damage, given the cost of the parts I’m working with. During the CPU and motherboard installation steps, I do wear an anti-static wrist strap as I work out of an abundance of caution — especially because I’m working during the winter, and the house is a bit dry and prone to static buildup on surfaces. So rather than probe about with a metal screwdriver, I prefer to start screws with a non-conductive screw-starter and grabber. It’s a small plunger-operated device that firmly holds screws in three metal “fingers”. Its grip is actually stronger than most magnetic screwdriver tips. They were once fairly common computer tools when circuit boards contained components that were more sensitive to magnetic fields, but seem to be uncommon today. Here’s a couple of pictures:

Once placed, the motherboard screws can be snugged down, but not too tightly. Just tight enough to hold firm and contact the solder points around each screw hole that provide ground connections. Check one more time that the ground tab on the connector shield is firmly up against the side of the USB connector’s metal shield, both from inside the case and outside.

This is a good time to verify that the connectors are all correctly positioned in the shield. Test-fit plugs into each. I found that the Ethernet connector’s tab wouldn’t lock in place because the metal cutout was blocking it slightly. I used a small flat-blade screwdriver to carefully press in and bend down the edge of the metal plate where it interfered.

With the motherboard mounted, it’s time to start filling in around. The power supply is next. This particular unit comes with optional silicone anti-vibration dampers. They’re just molded silicone gaskets that slip over the ends of the power supply case. The power supply fits very tightly with them on and it requires a bit of firm pressure as the screws are tightened. Note that the Antec 900 case only allows the power supply to be installed with the large intake fan on top, not the increasingly popular “inverted” arrangement that needs a vent cut in the case floor. I actually prefer this style — even with a filter, the inverted setup is likely to pull in carpet lint and floor dust which either clogs the filter or gets into the power supply. This arrangement pulls in warmer air from inside the case, but it should not be an issue in a case with as much airflow as this one.

Time to start on the case wiring. The front panel wiring is relatively simple. ASUS supplies a small connection block that’s clearly marked for the typical connections. The Antec 900 case only has a power button, reset button, and a drive activity LED. (There’s no power indicator light; the case fans are illuminated to show power on.) When all the front panel connectors are attached to the connection block, it’s easy to plug the block onto the motherboard header provided for the panel connections.

More front panel connections follow. The USB 3 connector goes to a matching header on the motherboard, as does the audio (headphone and microphone jack) cable. The motherboard supports both HD Audio and older AC97 standards; the connector goes to the HD Audio header on the board.

Next, we add the motherboard power cables. The power supply is modular, which means that it has a number of power output plugs which can be individually connected using various types of cables as required. Several of the plugs are dedicated to specific purposes. In this case, he outputs are divided across two separate power delivery rails. One set of outputs is for the motherboard and drives, the other set is for graphics cards. You only need to plug in cables that are needed, which cuts down on the wiring mess.

The cables are routed through the case’s minimal cable management holes to keep them out of the way of other connections on the motherboard.

With the basic power cabling in place, we move on to accessory and hard drive cables. The optical drive goes in the top 5 1/4″ drive bay, and its power cable was run as part of the bundle when the motherboard power cables were run. Now we move down the drive bay stack to the two 3 1/2″ drive carriers that are part of the case. Each carrier can hold three drives.

There will be two hard drives permanently installed — one for Windows and ordinary applications to run from, and a second to hold large, disk-intensive applications like MSTS/Open Rails, Flight Simulator X, and complex games. (The third bay will also be temporarily be used to hold a secondary Windows boot drive for my wife, who will be getting a similar system built around the same components.) All the hard drives will be installed in the bottom carrier, which has a case fan at the front blowing cool air across the drives and into the power supply area, which also supplies intake air for the power supply.

The upper hard drive carrier will be empty, and it instead forms part of the cooling arrangement for the case. Like the bottom bay, there is a case fan in the front. The back of the carrier also has an optional fan mount, so that it becomes a forced-air cooling duct. The fan which was removed from the rear case exhaust location will be attached to the interior end of the cooling duct arrangement. This will then push outside air directly toward the edge of the graphics card and its heatsink. In fact, the end of the graphics card will nearly line up with the center of this fan duct arrangement, so that the incoming airflow will be split between the graphics card area and power supply below, and the memory and CPU area above. If a longer graphics card were installed, the second fan could be removed and the card would be closer to the incoming air moved by the first fan anyway. This is a situation where you can take different options depending on your build needs. In any case, it’s best if you can place the graphics card in a clear incoming cool air path rather than behind a stack of hard drives.

At this stage, it’s time to work out the arrangement of the case fan power cables — there are four of them. One is from the top 200mm fan, and the other three are from the two case front fans and the one rear fan in the duct, which is still considered a case fan. Luckily, this motherboard has exactly four case fan connections. Not all boards do, and in such a case you’ll either need a fan wiring y-adapter somewhere or an accessory fan controller. But in this case, each fan can go to an individual connector on the motherboard and each can be individually set up and controlled by the board’s BIOS. The wires are neatly tucked in and around the existing wiring bundle wherever possible. There is also room behind the metal drive bay wall on the motherboard side to tuck wiring, and it can even be tied to the unused screw slots and holes with small zip ties. So there are wire management tricks in the Antec 900 case — they just aren’t obvious.

The fans were set up first because their wiring needs to lie close to the motherboard and can be bundled with the layer of power cables that is already in place. The next layer of wiring will be the SATA data cables for the drives, so they go in next. The drives are mounted in the lower 3 1/2″ drive carrier, and the carrier is then fixed in place. Next, the SATA data cables are connected between the drives and the motherboard (and at this time, the optical drive’s SATA cable is also run) and the modular power cables for the drives are also selected and connected.

Now it’s time to move to the upper area of the case — and the CPU cooler. Air-cooled heatsinks have been the standard cooling method for years, but to keep up with the heat output of faster CPUs, they’ve gotten huge and heavy. There were some early issues with damage to Skylake processors due to the high clamp force needed to keep oversize heatsinks in contact with the CPU, and even before, there have been problems with hanging large, heavy heatsinks off of the motherboard.

All-in one, closed-loop water coolers have become more practical and effective in recent years. Good enough that I wanted to try one in my Skylake build, so I could avoid the potential problems of heavy heatsinks and high-speed fan noise. The only problem was that most liquid cooling systems require rectangular radiators cooled by two 120mm or 140mm fans — neither of which can fit in the case I preferred.

Corsair’s H80 series cooler presented a possible solution, however. While the original version of it and other square single-fan 120mm radiators couldn’t outperform moderate to high-end air cooling, the H80i version had evolved into a extra-thick radiator with two push-pull fans and a more efficient pump and water block. On Intel Broadwell series processors, the H80i could come close to the performance of the larger rectangular H100. Given the improved thermal performance that the Skylake processor was said to have, the H80i looked promising. By the time I ordered my components, it had been updated to H80i V2 with a slightly improved pump which was even better.

In my build, the cooler’s radiator and push-pull fan assembly mounts in the back of the case where the exhaust fan normally goes. It’s set up to instead cooler air in from the rear vent. The warmer air removed from the radiator is exhausted by the large 200mm fan in the top of the case. The 200mm fan can move far more cubic feet of air per minute at lower, quieter speed than a common 120mm exhaust fan, and the exhaust pattern is moved to the natural upward convection air motion. Additionally, there are more fans working together to move denser, cool air into the lower areas of the case; the pressure will tend to force warm, less dense air out the top anyway.

This ASUS motherboard has complete power and control for water cooling built-in. This isn’t a common motherboard feature, so my installation differs from Corsair’s normal installation.

The radiator fans are connected to the dual CPU fan headers on the motherboard, which are normally used for push-pull air cooler setups. The pump is powered by a dedicated water pump header on the motherboard. In this setup, the pump and the fans can be individually controlled based on CPU temperature by the motherboard BIOS. The H80i has a multi-speed pump which can benefit from running at low speed for idle and low CPU temperature — it’s quiet and allows the coolant to absorb more heat as it circulates. At higher temperatures, the pump goes to full speed. Any pump noise is masked by the case fans’ increased speed at that point.

The normal installation of this cooler has the pump attached to the CPU fan header, and a wiring adapter powers the radiator fans. A USB cable runs from the pump to a USB 2 header on the motherboard for additional power and to control the pump and fans by software. This setup works for typical motherboards, but it lacks the fine-tuning ability of a motherboard engineered to support water cooling. Corsair’s software also isn’t universally praised, either, so it’s more effective to use the advanced BIOS of the motherboard. In my installation, the USB connection is not needed, so the cable is fastened up out of the way and tucked behind the motherboard power cables in the top of the case. The only feature lost by not connecting the USB cable is the ability to control the RGB LED logo on the pump, which isn’t important to me. It will light up white all the time, which is fine.

The water block mounts to the motherboard with a bracket that supports it from the back of the motherboard through the heatsink attachment holes. This is how large air coolers mount as well, but this assembly is lighter and designed to limit the amount of clamping force put on the CPU to the standard recommended by Intel.

The cooler comes with thermal compound already applied. It’s probably some variety of Shin Etsu compound, which has a good reputation. Most of the time I would say it’s fine to use it as-is. Since this system is going to be overclocked beyond the expected use of this cooler, though, I decided to spend a little more for a tube of Gelid’s GC-Extreme thermal paste.

Preparing the CPU heat spreader and the cold plate of the water block takes a little extra preparation. First, the pre-applied compound is wiped off the water block. A paper coffee filter works well for this. Cotton swabs and isopropyl alcohol can be used to clean the surfaces of the water block and the CPU heat spreader. Then it’s time to “tint” or “season” both metal surfaces with a small amount of the GC-Extreme paste. Just put a tiny bit on each surface and rub it on with the coffee filter material until it’s burnished lightly with an extremely thin, virtually invisible film of the thermal compound. This helps fill in the microscopic irregularity of the metal surfaces, which means that the final application of thermal compound will spread evenly and easily.

To apply the GC-Extreme compound, it’s recommended to warm it first. I put the applicator syringe in a plastic zip bag and dunked it in a cup of hot water from the tea kettle (around 190F – 200F) for about 30-45 seconds. Then, just squeeze a small blob of thermal compound — no bigger than a grain of rice — onto the center of the CPU heat spreader. There’s no need to spread it out, (You can discard the tiny spatula included with the thermal compound.) and avoid using too much. No more than a grain of rice! The tube of compound will have enough for several applications.

Fit the water block over the standoffs carefully and attach the finger-nuts onto the standoffs; the hoses are stiff and will tend to hold the water block away from the CPU which is fine. Once the hold-down nuts are threaded on, lower the water block gently and firmly straight down onto the CPU. Spin two nuts, diagonal from each other, down until they help hold the water block evenly while still keeping even pressure on it with one hand. You’ll feel it snugging the backing bracket firmly against the motherboard as you do so. Spin the other two nuts down and get them all evenly tight with your fingers. Finish by snugging them down with a Phillips screwdriver tip. They will stop positively when they are fully tightened — the standoffs are designed to prevent the hold-down nuts from being over-torqued.

With the cooling loop installed, the last step is to install the graphics card. I’m using a factory overclocked Nvidia GTX 960 from ASUS. Since I only have room for a 1440×900 monitor, I’m not pushing pixels like many folks with larger monitors. Unlike many gaming builds, I decided I could save money by choosing a very capable, but lower performance-bracket GPU and instead put more into the CPU, since much of what I run — Open Rails and Flight Simulator X — are CPU-dependent. I also do a fair amount of retro-gaming and console emulation, so CPU performance is key. With the next generation of Nvidia cards just around the corner when I first built this system, I didn’t want to spend too much now since I plan to upgrade the GPU in a year or two.

And the build is complete at this point. There was a final bit of mechanical modification necessary — the case has a clear plastic window on the removable side, and there is a pair of clips molded into the plastic to attach a side-mounted fan. One of the clips won’t fit past the radiator and fan assembly for the cooler. I removed the window insert and used a Dremel tool with a cut-off wheel to slice both clips off. This really isn’t a fault of the case design; it was never intended to be set up in this configuration. It’s still possible to mount a side fan with screws; the clips are a convenience, but not essential. I’ve never liked side fans though, because their wiring complicates removing the side panel, and they can cause rattles and vibration noise if the side panel doesn’t fit perfectly. The fan opening is covered by a metal mesh grille, and it adds one more place for cool air to enter the case or warm air to exit, much like the vent holes in and around the expansion slots do, so I’m leaving it as-is.

Now that it’s complete, how does it perform? Extremely well, as a matter of fact. I expected that my non-standard case airflow design and the H80i liquid cooler would allow me to run a moderate overclock without heat issues. I was pleasantly surprised to discover that this build will support a reliable, everyday overclock to 4.9GHz with no problems at all!

And it does so without being noisy. At idle, the fans are running so slowly that there’s just a quiet hum — quieter than many pre-built desktop PCs. Under load, the fans step up and become audible, but not enough to even raise your voice to be heard over. At full speed, there’s a steady, authoritative whoosh from the fans, but it’s nowhere near the jet-engine-under-the-desk noise that many air-cooled PCs make, or the noise of a rack-mount server at full scream that some overclocked PCs approach.

Coming up, I’ll post more technical details about this system. I’ve built numerous custom PCs over the years, and this one is by far the best ever in terms of both raw performance and performance versus cost.

Basic Stats:

• Total system cost: $1600.00 US Dollars, approximate. (Component prices vary.)
• Motherboard – ASUS Maximus VIII Hero (Intel Z170 chipset)
• Stock Intel Core i7 6700K CPU speed: 4.0GHz (Turbo Boost burst to 4.2GHz)
• Overclock Speed: 4.9GHz normal use / 5GHz stable benchmark test speed
• CPU liquid cooling with Corsair H80i V2
• 16GB DDR-4 memory at 3.0GHz (G.Skill Ripjaws V)
• Nvidia GTX 960 GPU with 4GB VRAM, overclocked to 1.4GHz max Boost Clock
• Power supply required – 650 Watts
• Antec 900 v3 case with modified airflow pattern