Yes, you should have both CPU power cables for proper connectivity.
Yes, you should have both CPU power cables for proper connectivity.
Upgrading to an Intel i9-14900K requires careful planning. With a semi-modular PSU and only one CPU power cable, you should run only one cable unless you have another one available. Check if your PCIE slot supports the new cable—some models restrict mixing cables. Since you can’t mix cables, it’s best to avoid using the existing one and get a compatible replacement. Your motherboard (MSI MAG Z790) should work with the right adapter, but confirm compatibility before purchasing.
The 14900K is the latest CPU model where you'd prefer more than one 8-pin connector. If you have an extra PCIe cable, you can use an adapter to convert it to a 4-pin EPS and run it instead. Make sure the cables match the PSU's pin configuration. Purchasing new cables is fine, but they should be tailored to your specific power supply.
I wouldn't rely on a 1600W unit lacking at least two EPS connectors—it looks quite questionable. For a 14900K build using EPS cables, you're right to expect more than just basic capacity; these cables are typically rated for around 235W continuously. To stay within the intended specifications, you'll need two connectors on any chip that can handle that power consistently, which top LGA1700 chips do. Most PSUs designed for such a setup should already include two EPS ports by default, so it makes sense to use them.
The review mentions built-in cables: 4+4 pin EPS12V/ATX12V (700mm) and 1 8 pin EPS12V (700mm). The 4+4 fits into one of the eight-pin connectors, while the 8-pin EPS12V goes into the other. PCI-E (red) headers are pre-pinned for those connectors; you can view them in the images here: https://www.techpowerup.com/review/rosew...600/4.html. You can design your own custom cables by rearranging the pins.
No, it's not possible. Your Rosewill Hercules is designed by Hipower / Sirtec, and the connections aren't confirmed to work with all systems. As illustrated in the images, the PSU headers for PCI-E follow a specific layout: 12------- 12v---- 12v--- ground-ground-ground-ground. Corsair power supplies use a similar format: 12------- 12v---- 12v--- 12v ground-ground-ground-ground. This setup allows compatibility with EPS cables for CPUs. Corsair provides two ground wires in their connectors, which should connect to the PSU header pins in PCI-E cables. Using Corsair cables can cause a short circuit between the 12v and the top-right ground pin, potentially preventing the PSU from starting or damaging it entirely.
They really have potential. My 7980XE can surpass the standard rating for 2 EPS connectors, though the cables work just fine. I don’t understand why you’d want to go beyond that limit when it’s possible to stay within it—remember, a 1600W unit should definitely include 2 EPS cables, and I’m not sure where the person getting this info got their idea.