[?] bad mobo? pcu? other?

[allenpan]

[?] bad mobo? pcu? other?

here is a scoop, my usb 2.0 ports for somereason does not provide enought current, and it happen to my current board and previous board, however, if u put in a NEC usb 2.0 PCI card, those USB ports on the NEC PCI card, they provide enought current...

so whats the problem? Mobo? PSU? other????

current board: ASUS P5Q-E
previous board: Intel DG33TL

PSU: OCZ GameXStream 850w

other spec:
Nvidia Prototyle GTX570
Q6700
8GB OCZ DDR2
3x 2TB Seagate Baracuda XT

i am refering to even the normal range: normal current, at least 200mA - 500mA

 

[ShintaiDK]

Enough current for what? There are 2 kinds of USB ports so to say, normal and high current.

 

[allenpan]

normal current, at least 200mA - 500mA

 

[mfenn]

That's an issue with your motherboard. The PSU has no way of distinguishing between where 5V power is going once it hits the ATX connector, the motherboard controls how much to provide to the PCI slots and the onboard USB headers.

 

[allenpan]

you sure? b/c as i mention i have 2 boards and they act the same, could it be the voltage regulation on the PSU? to my understanding PCI bus uses regulator to lower to 3.3V/5V using 12V rail... while the USB is using directly from 5V

 

[mfenn]

you sure? b/c as i mention i have 2 boards and they act the same, could it be the voltage regulation on the PSU? to my understanding PCI bus uses regulator to lower to 3.3V/5V using 12V rail... while the USB is using directly from 5V

Not in any motherboard design I've seen. It doesn't make sense (financially or engineering-wise) to step down a voltage that the PSU already provides. The ATX connector has 3.3V and 5V wires for a reason.

 

[allenpan]

guess what, it is the PSU, i brought the PSU to my lab and take it look using my osciliscope, the ripple is too much

 

[Sonikku]

Betther the PSU than the mobo at least. :thumbsup: