Which PSU for an ASRock Z170 EXTREME 7+ motherboard with many hard drives?

Question

I had the opportunity to acquire a second hand ASRock Z170 EXTREME 7+ mainboard at a good price and plan to assemble a tower to perform data recovery jobs.

It is a high-end board, whith 10 SATA III ports, 3 SATA Express, 4 PCIe-3.0 x16 slots, USB 3.1 A+C ports, M.2, a.s.o. Specifications are here: http://www.asrock.com/mb/Intel/Z170%20Extreme7+/?cat=Specifications

As working with hard drives that are possibly hardware defective, the quality of the power supply unit is important.

I plan to use:

• 2 or 3 dual drives hot swap bays, each accepting one 3.5'' and one 2.5'' hard drive, but having a unique SATA power socket
• 1 CD/DVD bay
• 1 floppy bay
• 1 to 3 SATA hard drives with miscellaneous operating systems, directly connected to the motherboard

So, the SATA power cables for permanently connected devices should be 8, although most of the time 3 to 5 should be in use. For the most busy days, I would like however the PSU to support more than 5 devices.

The remaining SATA ports will be used to connect other hard drives, when all SATA bays are full or for diagnostic purposes.

Probably 2 or 3 PCIe expansion cards will be in use (things like the PC-3000, MRT, ...) and possibly a graphic card.

I've not chosen the processor yet, but it will be an Intel i5 or i7 of 6th or 7th generation. The RAM was not chosen yet, but will be dual channel DDR4, probably 8 GB or 16 GB, as huge quantity of RAM is not necessary in this case.

Gaming performance is not required and graphic needs should be moderate, mainly for post-processing of recovered pictures through thumbnails view. So, what is required is a solid "technician desktop" with many hardware extensions, but moderate processing needs.

The stability of the whole is essential.

I would like the cables to be long enough to reach the SATA bays easily.

So, how many Watts should the PSU support?

Which brands / families / models would you recommend, taking into acount "old" series, as I prefer a second hand high-end model to a medium range new model?

To the precence of which kind of power connectors (other than SATA ones) should I pay attention as well?

Alghough I'm used to upgrading hardware, this is my first attempt for a self-made tower. Thank you for your help.

Answer 1

I ended up acquiring an almost new Corsair AX760i PSU which was sold ~115 USD, which is almost half its new price. It 80 PLUS® Platinum Certified Fully-Modular PSU.

What I learned it that there are several class of energy conversion efficiency certifications. The 80 PLUS certification ensures that the energy conversion efficiency is at least 80%. Above 80% are further "80 Plus ..." certifications : Bronze (82%), Silver (85%), Gold (85%), Platinium (90%), Titanium (92%).

Some constructors have an online calculator to estimate the power consumption of the computer. Even with the several drives and expansion cards mentioned in my original post, the estimated consumption was around 360W. A very high supported wattage is useless for most users, at least for office users. However, high wattage PSUs usually have more cables. For instance, my 760 W power supply unit comes with 3 SATA cables, each with 4 SATA connectors, 4 PCI-e cables, and several other cables. It will be perfect for my motherboard which has 3 PCI-E sockets and as I can power 3 hard drives with independant cables.

In comparison, the 1200 Watts AX1200i comes with 4 SATA cables and 6 PCI-E cables. I believe that some of the high wattage units are also designed to adapt with some high end motherboards of the future, which will probably have more PCI-E sockets.

The are three kind of power supply units: - non modular - semi modular - fully modular The difference if is the cables are permanently attached to the PSU or if you can attach or remove them. A fully modular PSU allows to attach/detach all cables, whilst a semi-modular one has the main cables attached permanently and others than you can add/remove depending on your needs. The more modular the PSU, the more comfort, but also the higher the price. If you don't plan changes to your hardware, a non modular or semi modular PSU will suffice.

One thing to mention is tha high end PSUs seem coming with more advanced voltage regulation. For instance, according to the manual, the AXi serie from Corsair uses a Digital Signal Processor (DSP) which improves overall system stability and component reliability. They also have better fan control, as the fan is activated only when necessary.

From what I read, some manufacturers, like Seasonic produce supply units which are then commercialized by miscellaneous brands, like Corsair.