The bandwidth thing is easy to understand as pci-e is made for fast speed. Even if the bandwidth is shared between the four ports of a pcie card it would exceed the nominal bandwidth of any USB on the motherboard. And as you said, an external hub is sharing the bandwidth of a single port. I guess bandwidth is rarely an issue even when duplicating external disks. Noticeable, maybe, but not critical.
But how about power delivery? That's what causes the brownouts. Do internal pcie USB cards provide full power to each of the four ports?
Just from experience, didn’t read up on PCI vs Hub power distro.
Power is stationary, IE, 14 watts output is 14 watts. However that connected devise distributes it makes it variable. Data is a variable rate.
Example: the LEDs lights on a x52 is its own worst enemy. They will steal power from the operation of the stick. The stick will have less spiking if LEDs are turned off. Its power distribution puts cute lights equal to or above operations as they are 100% constantly (you can dim them to free up power too). Which reminds me of series wiring/distro, or series-parallel. Lights and operation.
Because the PCIe cards have many pins its probably more consistent, because now we get into a hub’s quality that should transformer the voltage equally to each output. This may be where price comes in. Are you paying for quality transformers that balance it equally. This may apply to PCI too. Remember, cables can have or develop resistance. A direct connection will have less resistance. The longer the cable the more resistance. Just a poor cable using can make you drop from 14 watts to 13.7.
Example: for digital sound systems we use cat5 or cat6. The longest you can use is 500ft. We often use 300ft from backstage to FOH (house mixer). If you need to extend to 500 it takes a another RIO box to join the extension without one constant 300’ or 500’ cable. Yet with copper I can use it at 500’ with little problems, it will carry more. Optic fiber is the way to go.
Point being, a direct connection will always be more stable. What ya lose is that resistance of a crappy cable. They are not all made the same.
Back to the diode thing. It allows power to pass on the circuit board, kinda like a resister or capacitor. Except it has a switching system according to heat to protect the board. Depending on its design, when it reaches a certain temp it will trigger that switch to kill power. When your video card shuts down from heat that diode needs to cool down before it opens again. Its a breaker. Its work like a thermostat on a car engine. But the opposite.
I’ve fix “blown” components by testing the diodes finding a bad one with a scope, replacing, fires right up at $1 part. But you’ll get charged in the $100s because you have no idea its a $1 piece they fixed in 1 hr. Its one of the most common fixes. In the old days a diode was done with a tube.
In a lightning strike its too fast for the diode to protect it.
So, my guess a PCI will be more consistent and predictable.
When I have a sound system issue, 95% of the time its a cable, not the component.
