Originally Posted by Phaedrus2129;14531169
This is going to cause some PSU issues. Modern PSUs are not designed for such heavy loads on the +5V rail, especially cheap group regulated ones.
Originally Posted by Phaedrus2129;14531240
I mean, if you ran a 100W laptop off a Corsair CX430 that was also powering a computer, the PSU would just shut down. I mean it can only do 20A@+5V, which is 100W; an average computer pulls 30-50W on that rail, so 130-150W exceeds the PSU's design parameters. Not to mention if you're doing this at idle the +12V load will be very low, so you get a crossloading situation. The +5V voltage goes way low, and the +12V voltage goes way high. There's potential for component damage there, and system instability. Low +5V can cause a hard drive head crash.
Most PSUs in pre-built systems are even less capable than the CX430 in this regard.
They could redesign these PSUs to have more +5V capacity, but that seems a step backward as we've been phasing these voltages out slowly since 2001.
I agree entirely. 100W off of the 5V rail just seems ridiculous, especially if you think about the amount of current required to push it through such a narrow gauge of wire. I don't have the numbers to hand, but wouldn't the required wattage be far higher?
Originally Posted by Killam0n;14555097
This will be on the 12v PSU rail
USB4.0 not 3.0
This is a good thing, most electronic components already run off of 12v take many printers for instance, the wall plug in is just converted from AC to DC around 12v to run your printer. This could then make your printer more power efficient because its crappy power converter is then not always sucking juice from the wall.
Are you sure it will be on the 12v rail? I read the article and can see no mention of it. To quote one of the replies to it though:That's 20 amps at 5V. The USB cable would have to be the size of a heavy duty extension cord for that.
What's more, the low voltage means that even tiny amounts of resistance in the connectors and or wiring will cost you huge percentages of your total power. for 5V@20a , every 0.025 ohms resistance in the wiring will cost you 10% of the total power available.
It might be possible to help this by increasing the voltage and reducing the current. Bringing the voltage up to 12V would reduce the current requirements to 8.333A, a significant improvement, but that would also bring compatibility issues with older 5V only equipment.
Even operating at 12v, we'd need to see thicker gauge wires to push out 100V. I could potentially see them adding a dual power option, with 12v or 5v, but making USB4 plugs
compatible with USB3 ports would mean fitting a 12v input/output "pin" into USB's already cramped innards, would it not? Or would we get some "smart" ports that could accidentally roast appliances when the drivers sent out 12v instead of 5v?
I'm all for a move to 12v, but surely a different plug would be beneficial for such a large change in specification? Keeping it "USB" is not a great idea from where I'm standing.
Also, imagine netbooks trying to draw an additional 100W of power? Or, if that's turned off, your average generic PSU that normally only draws 150-200W going up by another 100W? 300W of power draw is often too much for brandless units, regardless of the rail that the majority is on.