In the time it takes just to expose the motherboard (HSF removed, expansion cards pulled, power connectors pulled, FP connectors removed, USB headers disconnected, SATA drives disconnected, etc.) you could have already had the PSU disconnected and out of the computer. I'm not even talking the 6+ screws unscrewed yet either. Then you might have a really cramped case where optical drives have to be slid forward just to maneuver the unscrewed motherboard to get it out of the case. It's a big job...the biggest in computer repair.
Again, this depends entirely on the build. If your PSU is fully modular and there's room to move it around/get at the connectors it is indeed trivial to replace; the same would be true for a non-modular unit if the cabling is the last thing installed in a relatively open space and not tied down. If you need to remove and re-run cabling, especially if this is zip-tied in place or you need to be tidy to fit a tight-fitting side panel on, this can take a long, long time unless you enjoy pinching cables and bending side panels. Replacing the motherboard doesn't require you to
remove any cabling whatsoever in any modern ATX case with decent cutouts: just disconnect it from the board (relatively easy outside of tight 24-pins), unplug any AICs (usually easy, 1-2 screws), and pull the board (4-9 screws). Sure, there are some screws involved, but there are 4 screws holding standard PSUs in place too. The cooler is best left on until the board is out unless it's an AIO or otherwise mounted to the case. In an average semi-budget build (air cooled CPU, one GPU, semi-modular PSU, case without lots of room for cable routing) I would say a motherboard replacement can be a lot quicker than a PSU replacement.
Just look at what OEMs have where repair is a chief concern of theirs in engineering: I have an HP Ultra-Sim here and the PSU can literally be removed from the computer without any tools in less than a minute. A new one replacing it in less than a minute, also without tools.
Absolutely. The problem is those PSUs (and motherboards!) are tailor made for each other with cable runs and everything else made to fit that exact use case perfectly, so you're comparing apples to oranges. Standard form factor builds don't work like this. Beyond that, these OEM SFF PCs often ignore standards too - while I'm only familiar with Dells of this form factor, they have long since abandoned the ATX PSU voltage output standard and ditched the legacy voltages. IIRC modern Dell SFF PCs use 8- or 10-pin PSU connectors, and generate 3.3V and 5V for SATA power on the motherboard with the PSU only providing 12V and 5VSB.
Replace the motherboard? At least a thirty minute job and doing so invalidates all of the identification stickers on the machine. Better off recycling it and just moving the equipment to a different, machine of the same model.
Well, yes, because that's how those machines are designed. Saying "the part that's designed to go in first is the takes the longest to replace" as if it is an argument for anything is ... odd. That would be true whatever that component was. If the PC was designed so that the PSU was the first part installed it would also be the slowest part to replace.
I've never seen a motherboard designed to be serviceable. PSUs almost always are, fully modular especially so.
...guess that depends on your definition of "serviceable". Sure, less SMDs in a PSU, easier to solder by hand and the components used are more widely available, but neither of these parts are really serviceable outside of professional repair centres. (That doesn't mean a dedicated and knowledgeable hobbyist can't repair a PSU, but hot air soldering/desoldering of VRM components on a motherboard isn't that much more advanced than repairing a PSU. Parts availability is more complicated, though.)
Quality PSUs have overcurrent protection so they *can't.* I've yet to have a PSU kill a motherboard but I've never skimped on power supplies either.
I haven't either, but there are plenty of horror stories out there. The majority of those are probably either old or use terrible PSUs, but wouldn't simplifying PSU design then help in this regard?
PSUs always have better overcurrent protection than motherboards.
...but we're talking about a fundamental design change here. Don't you think good OCP would be a desirable feature for motherboards featuring these onboard voltage regulators?
PSUs shunt the power to ground. The quicker and closer the circuit is closed to the AC source, the less damage is possible down the line.
Doesn't that depend on where the failure happens? Also, aren't PC cases - and thus motherboards - grounded, and wouldn't any onboard voltage converter then also be designed to shunt power to ground? Beyond that, the only difference between this (12V out from PSU, various lower voltages generated on the motherboard) and current high-end PSUs (12V generated in the PSU, converted internally to 5V and 3.3V) is where conversion happens, and that one locks you into a given set of voltages while the other allows for whatever is needed, including ditching unnecessary voltages. IMO the latter is far superior.
I think the best solution is the return of the slot processor. An AIB gets power directly from the PSU at a given voltage and handles the power delivery to the socket. Part of the PSU, therefore, becomes part of the motherboard but still allowing for replacement and higher quality control of defective part. This also allows any motherboard to be adjusted according to the power demands of the processor installed. Graphics cards pretty much already do this. The same concept should apply to CPUs.
Slotting CPU also gives it its own thermal domain by nature. The problem is the DIMMs really need to be on the AIB too because of the sheer number of electrical connections they require.
I don't entirely disagree here, but it would be very very inefficient in terms of space usage (the CPU+VRM+RAM AIC would need to be close to the size of an ITX board, and you'd lose a lot of freedom in terms of putting components where they fit best) and you'd introduce an extra connector in the PCIe signal path while also increasing its length. Cooler compatibility with a slot-in card would also be problematic, though a lot of this could be solved by using a parallel rather than perpendicular daughter board (stacked boards are space efficient and you'd avoid the problem of having tower coolers hanging off a 90-degree angled AIC and colliding with the board below). You'd still have a lot of issues with I/O, though, and would likely drive up prices due to needing more external controllers (or needing a bunch of pins for all the internal controllers on a modern CPU).
Increases the cost and complexity of motherboards.
Nowhere near as much as high bandwidth buses like DDR5 or PCIe 4.0/5.0. In comparison the cost addition would be negligible, and the total cost might even drop due to removing unnecessary components. This should make PSUs significantly cheaper and more efficient at the same time.
TL;DR: This idea is great for trying to establish a power supply standard for SFF computers but it's not the best path forward for replacing ATX in regards to power supply.
Have to disagree with you here. The ATX PSU standard stems from a time when DC-DC voltage conversion wasn't as trivial and efficient as it is today and the PSU thus created three major voltages directly from AC. The majority of desktop PCs today are also some form of SFF (as in "not an ATX mid-tower or bigger"). And the brilliance of simplifying the PSU like this is that one size fits all - if you have a huge PC with lots of weird AICs needing weird voltages you can convert them all from 12V, but you don't need to waste space on those voltage converters unless you actually need them. On the other hand a design trying to be everything for everyone - like the current ATX standard - will inevitably be more than what's necessary for the vast majority of use cases.