A few days ago, we reported on a story from Tom's Hardware about the power on offer from PCI Express 4.0 expansion slots. Tom's had been in touch with PCI-SIG, the governing body of the standard, and the site reported that PCI Express 4.0 would not only double the throughput of PCIe 3.0, but that it would also allow expansion cards to draw "a minimum of 300W" from the motherboard.
As it happens, the data on PCIe 4.0's upgraded bandwidth was accurate, but apparently someone at PCI-SIG gave Tom's incorrect information regarding the power provisions in the new standard. Currently, PCI Express 3.0 cards may draw 75W from the expansion slot, and an additional 225W from auxiliary connectors, for a total of 300W. PCIe 4.0 devices may be allowed to draw more than 300W in total power. However, the power provided by the slot itself will remain at 75 watts. Folks hoping for a slot-powered GTX 1180 or Radeon Fury RX will probably have to keep dreaming.