Now is a good time to build a Kaby Lake system, provided you're not holding out for Coffee Lake. With Intel having announced its 8th generation Core desktop processor family over the weekend, there are deals to be had on what are now previous generation products. One of them is for an Asus ROG Strix Z270F Gaming motherboard.
One thing to keep in mind is that Coffee Lake CPUs are not supported on Z270 motherboards. That means you're looking at a platform overhaul if and when you decide to upgrade. On the flip side, Intel is currently preventing Z370 motherboards from supporting Kaby Lake processors via firmware, so if you're building a new system, it's a choice between spending a bit more to have the newest architecture, or saving a few bucks by rolling with Kaby Lake.
If you're willing to take the latter option, this Asus motherboard is a good place to start. It has two reinforced PCIe 3.0 x16 slots, a regular PCI3 3.0 x16 slot (max at x4 mode), and four PCI3 3.0 x1 slots. For storage, this board offers up six SATA 6Gbps ports and, for faster NVMe SSDs, two M.2 sockets.
You can grab this motherboard on sale here at Amazon and here at B&H. Both retailers also have Intel's Core i7-7700K on sale for $300 (here for Amazon, here for B&H). If you happen to live near a Micro Center, you can snag the CPU for $280, plus score a $30 discount if you bundle it with a compatible motherboard. One options would be to pair it with a Gigabyte GA-Z270-HD3 motherboard for $105. After the $30 bundle discount, you're looking at $355 for the two.
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