PCIe 4.0 standard will be finalized before the end of the year in order to accommodate the needs that we now have in the computer hardware segment. PCI-Express 3.0 has been with us for the last 7 years and we have not felt the need for something more until recently. Now that M.2 NVMe drives along with multiple GPUs for machine learning are being used we need much more than PCI-Express 3.0.
M.2 NVMe drives are becoming the standard in PC builds and machine learning needs faster solutions, that is where the PCIe 4.0 standard comes in. The PCIe 4.0 standard increases the interconnect frequency to 32 GHz and increases the bandwidth by 2 times to 64 Gb/s. It has also been confirmed that PCIe 4.0 will not stay for long.
PCIe 5.0 will replace it in 2018 according to PCI-SIG. PCIe 5.0 will enable 400 Gb ethernet solutions. The new standards will improve multi-GPU support and have the potential of making the SLI connectors obsolete. The bandwidth provided by the individual ports should be plenty.
Keeping all this in mind, now might not the best time to buy a motherboard unless you really have to. I would wait for the mainstream motherboards with the new PCIe 4.0 slots to come out before making a purchase. Your views regarding the matter could be different.
It is also important to note that AMD and Intel will have an important role in deciding when to release this standard in the consumer market. PCI-SIG can only provide the standard, it is AMD and Intel that are going to use the standard and introduce it into the consumer market. We will have to wait and see what Intel and AMD have to say regarding the matter.
Let us know what you think about PCIe 4.0 and whether or not you are going to wait for the standard to be released before buying a new motherboard.