Skylake mini-ITX build using non-K processor

We just started our first Skylake build on micro-ATX taking the Haswell build and using it with a system cost of $1500. The main changes with the Z170 board called the Gigabyte Z170MX-Gaming 5 is that we now get:

  • USB 3.1 Controller. So 16Gbps for 2 USB 3.1 ports (10Gbps is standard and is 2x the speed of USB 3.0)
  • USB C Connector
  • Way more space for a cooler. The DDR4 slots are much closer together so a fat cooler like the Shruken B can now fit which is great.
  • PCI Express 3.0 with NVMe so you can get 2GBps from a Samsung 950 Pro as a boot drive.

However, this is still a relatively expensive build because the chassis ($110) and the power supply are relatively big and it was designed for dual GPU setups which are pretty rare and when we tried it, the thing thermal throttled almost immediately with so much power in so little space. So the more economical build would do all this in a single slot mini-ITX form factor. So off to find a good build for this with the goals of:

  • Full slot Video card. At least the 280mm of the ASUS Strix 970
  • Full AT power supply as these are inexpensive. With a build like this, we also need just 450 watts or so given how efficient the Skylake is (65W)
  • USB 3.1 speeds to make it easy to put external drives and eventually monitors on these ports
  • USB C as this is also the future
  • Retains 32GB support so need DDR4 support to get 16GB modules.
  • 802.11ac wifi built in rather than on a dongle.

So what are some choices and some notes as documented in our Skylake mini-ITX build since we will rarely need to use a dual SLI configuration and in any case, using dual SLI air cooled in that chassis doesn’t work well, there is simply too much air to be moved if you are running full bore. This new configuration is smaller and costs less ($1300) mainly by getting a cheaper case and realizing that with Skylake, you don’t need as big a power supply (550 watts is fine).

The other big savings is that you no longer need a K processor to overclock since the BCLK for the processor is now separate from the PCIe bus. Gigabyte is one of the first to announce BIOS support for this, so here is where we gained and ASRock does it as well

  • Cases. The Thermaltake Core V1 seems very small and seems to support 285mm extenral dimensions so should just fit if you take out the drive bays and is much cheaper than the Silverstone SG-10B at $45 vs $110.
  • Processor. Skylake i6400 apparently can be overclocked, so there is probbly at $100 savings at least because you still get 30% overclock. But the 6300 is $189 vs the $260 of the 6600K and will get you to the same 4.4-4.5GHz overclock. The tradeoffs are there isn’t power management and you can’t use AVX instructions.
  • Motherboard. The interesting motherboard is the ASRock Z170M-ITX/ac which allow overclocking of less expensive non-K processors like the i-6500. But the Gigabyte Z170N Gaming 5 has 802.11ac, USB 3.1, USB-C, PCIe x 4 NVMe M.2 slot and has annoucne they will allow this. We also do not need an ugly spearate 802.11/ac dongle so a cost savings.
  • Shuriken B. This is $45 vs the $70 of the Noctua, it also has great specs, but needs lots of clearance next to the Ram coolers.

So we saved $200 but there are some parts that don’t change but which you could choose to reduce. The biggest one is SSD (a third of the cost is storage right now).

  • SSDs. The biggest variable is how much disk you need. Given the fallling prices, it might make sense to drop the $200 480GB data drive and that gets you very close to the mythical $1000 desktop price.
  • Graphics card. At $320, the GTX 970 remains a good value and if you are overclocking a non-K part, the onboard graphics are disabled.
  • Memory. 16GB for $100 is an incredible deal for DDR-3200 memory, but you could go to 32GB for $100 more, the most tempting thing to increase since the ITX only has two slots.
  • EGVA power supply. It is $650 and more like $65 than $80, but I’m not sure you really want to skimp on the supply. If anything, getting a high quality Seasonic unit is pretty tempting but add $15 more.