Linked by Thom Holwerda on Mon 6th Mar 2017 20:48 UTC
Hardware, Embedded Systems

Okay so I'm using this perfectly fine article as an excuse to bring something up, so bear with me here.

If you haven't been paying attention to the PC world lately, you might not have noticed that the lowly PC has seen a bit of a resurgence, with interesting designs and unique concepts. We saw this come to bear at CES just a couple of months ago, where PC makers such as Dell, Lenovo, and HP all trotted out interesting laptop designs.

But the laptop isn't the only PC that's seen a design-focused revival. The lowly desktop PC has transformed from a boring beige or black box into a centerpiece of a modern desk space. An all-in-one computer in 2017 is both functional as a computer and beautiful to appreciate as a piece of design.

This is only slightly related, but it's something that has been bugging me for years, and since I was confronted with it again this past weekend, I might as well get it out of my system: why is nobody innovating anymore in the field of building your own computer? So many aspects of building your own computer are completely crazy when you think about it, and it seems like nobody is really doing anything to fix them.

For instance, why haven't we come up with a way to increase the power you can draw from a PCI-E slot, so that graphics cards don't have to be plugged into the PSU directly with unwieldy power cables, with connectors in the most boneheaded location on the graphics card?

Why are we still using those horrible internal 9/10-pin connectors for USB, the front panel, audio, and so on? These are absolutely dreadful connectors, spread out all over the motherboard in illogical places forcing you to route cabling in unnatural ways, and the pins can easily bend. This is terrible 80s technology that we should've fixed by now.

And the most idiotic connector of them all, which is huge, stiff, almost impossible to plug in, remove, or route properly: the ATX power plug from the PSU to the motherboard. This thing is probably one of the worst connectors you can possibly find inside any computer, and the slot on the motherboard is in an incredibly illogical place considering most case layouts. To make matters worse, the CPU power connector sits at the top-left (usually) of the motherboard, so that's another unwieldy connector and cable with an unnatural route that you have to deal with. It's just terrible.

I like the inside of my computer to look as neat and tidy as possible - not only because it looks nice and is easier to clean, but also because it improves airflow, something quite important with today's processors and graphics cards. However, aging standards with terrible designs and horrible usability that wouldn't look out of place in a 1960s mainframe make that quite the challenge.

We've seen some minor improvements already these past ten years or so, with the advent of modular PSUs and the death of the dreadfully terrible IDE cables and Molex connectors, but more work is definitely needed. We need a replacement for the aging ATX standard, which delivers enough power to the motherboard for the board itself, video cards, and the processors and fans, through a single cable with a modern, easy-to-use connector. It'd be great if a replacement for SATA could also carry power, so that we no longer need to route individual power cables to our hard drives. We need to get rid of 9/10-pin connectors for things like USB and the front panel, and replace them with easy-to-use USB-like connectors.

And last but certainly not least: put all of these things in locations that make sense for the vast majority of cases in use today, so we can reduce the length of cables, save money in the process, and end up with cleaner, easier-to-use computers.

Intel, AMD, NVIDIA, case makers, Microsoft, and whomever else is involved here - sit around a damn table for once, and hash this stuff out. ATX is outdated garbage, and needs a modern replacement. ATX was introduced in 1995 - do you still want to use Windows 95? OS/2 Warp? Version 1.2.0 of the Linux kernel? System 7.5.1? Floppies? CRTs? Of course you don't!

Then why the hell are we still using ATX?

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RE: Comment by Luminair
by fmaxwell on Tue 7th Mar 2017 10:26 UTC in reply to "Comment by Luminair"
fmaxwell
Member since:
2005-11-13

1) I'm pretty sure power cables need to be thick


You are, of course, correct. Just for example, here are the specs of a Corsair RMX ATX power supply:

+3.3V@25A; +5V@25A; +12V@70.8A; -12V@0.8A; +15VSB@3A

You can't supply that kind of amperage without large connectors fed by massive amounts of copper.

Reply Parent Score: 3

v RE[2]: Comment by Luminair
by egarland on Tue 7th Mar 2017 12:57 in reply to "RE: Comment by Luminair"
RE[3]: Comment by Luminair
by ssokolow on Tue 7th Mar 2017 15:15 in reply to "RE[2]: Comment by Luminair"
ssokolow Member since:
2010-01-21

ATX power cables need to be thick.

Computers don't need thick power cables.

Look at a NUC. Look at a tablet. Look at a laptop. Computers need 2 wires, relatively thin. The way ATX delivers power is a mess. It's far more space efficient today to simply deliver 19-24V DC to the board and have it DC-DC voltage convert whatever it needs from that. Doing the conversion in the power supply is much less space and resource efficient and requires the supply to implement capabilities that are never used and run tons of basically pointless wires.


Previous commenters have already disproved that in several dozen ways.

The peak wattage requirements of Desktop PCs don't magically drop if you move the DC-DC conversion out of the PSU and the motherboard can only carry so much current, given that a thin PCB trace must be much wider than a fat wire to safely carry the same amount of current.

I have a desktop GPU that doesn't require an external power connector (a GeForce GTX750)... because I specifically decided I couldn't justify the cost of anything more powerful than a mobile GPU for the machine in question.

Edited 2017-03-07 15:19 UTC

Reply Parent Score: 2

RE[3]: Comment by Luminair
by Alfman on Tue 7th Mar 2017 15:42 in reply to "RE[2]: Comment by Luminair"
Alfman Member since:
2011-01-28

egarland,

ATX power cables need to be thick.

Computers don't need thick power cables.

Look at a NUC. Look at a tablet. Look at a laptop.


All of these typically sacrifice performance and peripherals for lower energy consumption. There's nothing wrong with that, but it's not an apples to apples comparison.

Computers need 2 wires, relatively thin. The way ATX delivers power is a mess. It's far more space efficient today to simply deliver 19-24V DC to the board and have it DC-DC voltage convert whatever it needs from that.


Or, why not just feed 120V or 240V with the thinnest wires possible and save 100% of the space that would be wasted by having a power supply at all? Right? Obviously I'm being sarcastic, but I'm trying to make a point that reducing complexity & wiring in and around the power supply needs to be measured against adding more complexity, expense, space, heat, fans, electrical noise, etc to other system components.

Doing the conversion in the power supply is much less space and resource efficient and requires the supply to implement capabilities that are never used and run tons of basically pointless wires.



Perhaps ATX does not hit the right balance, and you may be right about useless voltages, however a strait up 24V as you suggest would just end up shifting complexity IMHO.

Linear regulators are simple, but since they achieve lower voltage through resistance, most of the energy from your 24V supply would be lost to heat (and require heatsink/fan). If you propose using a buck regulator instead, you'll end up needing to build many mini power supplies, and I'm inclined to think that the sum of all these is less efficient, more expensive, and more failure prone than wiring up a primary power supply.

Any money saved by simplifying the primary power supply would likely result in more money lost on more expensive system components.

Reply Parent Score: 4

RE[3]: Comment by Luminair
by Luminair on Tue 7th Mar 2017 19:29 in reply to "RE[2]: Comment by Luminair"
Luminair Member since:
2007-03-30

I feel like this would be a new motherboard standard that shunts $50 of PSU components into $100 of motherboard components

Reply Parent Score: 4

RE[2]: Comment by Luminair
by oiaohm on Wed 8th Mar 2017 08:50 in reply to "RE: Comment by Luminair"
oiaohm Member since:
2009-05-30

This is where it gets interesting. Open compute Decathlete Server Motherboards that are x86 like the everything else only have +12V rails with a ground from the power-supply. None of this 3.3V or 5v or 15V.

Reduces complexity of tracks motherboard in fact down stepping the +5 and 3.3V on the motherboard anyhow. Because ATX motherboards end up having power filters on every rail anyhow because power supplies are not always good.

So there is really no logical reasons to keep the ATX plug with the boards that have already been made.

Remember the higher the voltage lower the amps the more current you get through a cable.

So a 3.3V 25A and 5V 25A and a 12V 25A are all about the same size cable.
3.3V is 82.5W
5V is 125W
12 is 300W
All over the same cable size.

The multi voltages in the ATX power cable trace to before we had highly effective and compact dc-dc converter circuits so required voltages had to come off a transformer in the power-supply.

So yes the power cable could be simplified a lot. The power supply could also be simplified a lot.

The issue is the circuits to make sure that 3.3 volts and 5 volts are correct on the motherboard are in fact bigger and more heat generating than putting dc-dc converters on the motherboard to provide those voltages. So when Decathlete Server Motherboards design as done they went it was pointless to have those voltages coming out of the power-supply. It 12V+ where dc-dc converting starts being bigger than regulating.

15V in ATX is also fairly much pointless in new systems that are PCI bus or better. -12V and +5 is pointless on systems that are pure PCI Express.

Why is PCI Express 5V pointless the PCI Expresses voltages are +12V +3.3V and ground.

Then you look at ram DDR3 used 1.5 and DDR4 uses 1.2 with a 2.5V. So you are going to DC-DC covert this anyhow. Then you get to your CPU voltages and you are going to DC-DC convert that again anyhow.

The reality is most of modern motherboards don't run on voltages that come from power supply.

So this bring the big question why are we still using ATX power supplies when we are just DC-DC converting on the motherboard anyhow. Even 3.3 volt for PCI-e is iffy to come into motherboard by power supply cable. Having to run the 3.3 volts cross the board to the PCI-e slots is a self a problem when you could have a dc-dc converter sitting off the 12 volt rails the PCI-e slots need.

Getting rid of the ATX board might be hard. But the ATX power-supply really does not suit how modern boards work.

Reply Parent Score: 2

RE[3]: Comment by Luminair
by aliquis on Thu 9th Mar 2017 01:48 in reply to "RE[2]: Comment by Luminair"
aliquis Member since:
2005-07-23

The upside down ATX = BTX is better.

I would kinda be ok simply with case fixing the ATX board upside down though.

Reply Parent Score: 2