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USB 2.0 Header Limitation

PeZzy
Level 7
I have a Kraken X62 and a 2 front case USB connections. I would like to have them all connected. I have 2 USB 3.0 connectors using the 3.0 header.

I bought this - 9-Pin USB Internal Header Y Splitter Cable + Molex Powered (5cm) - to split off the single USB 2.0 header on the motherboard.

Unfortunately, there seems to be a limitation of the USB 2.0 header that prevents more than two devices functioning off of it. Is this a hardware limitation or is it a BIOS limitation? I made sure USB 15 & 16 were enabled in the BIOS. It would be nice to get the 2.0 header "opened up" for more devices. There's far too many USB connections at the back - no one uses that many. I wish they had added one more 2.0 header to the motherboard.
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13 REPLIES 13

JustinThyme wrote:
You need a powered hub.
Im using the NZXT


https://www.newegg.com/Product/Product.aspx?Item=9SIA6KX5DC5917


How does the NZXT expansion work ? i a'm looking at it for 2 weeks now (i want to use my usb 2.0 card reader (internal) and mij USB 2.0 front headers but deu to lack of usb 2.0 header connector on mobo i only have the front usb ports plugged in now).
Dues the NZXT supports full speed of the USB 2.0 front header of my comp case and the max speed of my card read ?
Also do the USB 2.0 front ports work simontaineously with the card reader, or can i only use 1 at a time ? (with other words can i write/read from Sd cad with card reader and simontaineously read/write from sub stick in front usb header port, and how is the transfer/write spead then ?)

Korth
Level 14
The USB2 header on the motherboard is 1C/2P (Single Controller, Dual Port) - the header pinout has two sets of 4 pins each (for two USB2 ports), plus an "optional" signal ground pin (usually attached to shield on better USB cables), plus a "missing" or "blocked" pin for physical keying (so you don't plug the thing in backwards). You need something like this USB2 adapter to use both ports (ie: the "Y-splitters" mentioned in above posts).

The controller can provide up to 500mA to each of the two ports. Connected USB2 devices are initially provided "low power" (up to 50mA or 100mA) but must be properly enumerated (formally identify themselves and their functions/parameters to the operating system and USB drivers) before they can get more power. A dual port "Y-splitter" is electrically passive, it doesn't add any power. A passive multi-port USB hub simply splits one USB port into multiple USB ports - each "downstream" hub-connected USB device is given a share of the USB signal bandwidth and USB power (up to 500mW maximum provided by the "upstream" USB controller) - while an active/powered USB hub has it's own (molex) power input which can provide additional power to each "downstream" hub-connected USB device (required if total power requirements for all hub-connected USB devices exceeds 500mA). USB specs supposedly make it "impossible" to connect USB stuff improperly, but it's really not hard to exceed power demands on a crowded USB "cluster" (with up to 128 supported USB devices/ports per USB controller!) where insufficient/intermittent power supply causes the whole tangled mess to malfunction.

@JustinThyme's NZXT powered USB hub is a fine choice. But you can pick any powered USB2 hub with **the specific USB output ports you need** and whatever colour/style you like. You'd connect the motherboard USB2 header (and a molex power input) to the powered USB2 hub, then connect the hub to your variety of USB devices (inside or outside the PC chassis, as you prefer). Power supply for all USB2 devices shouldn't ever be an issue, but total signal bandwidth from each USB2 controller ("High Speed" up to 480Mbps=60MB/s) is shared across every active "downstream" USB device it services, so performance-based USB devices (fast flash drives, card readers, etc) could be slowed down when their combined bandwidth demands exceed the USB2 controller's maximum limits. The only way for multiple USB devices to all simultaneously operate at maximum speed is to connect each one to a separate USB controller (on the motherboard). This isn't an issue with low-bandwidth USB devices (like the Kraken X62) which don't require much signalling (to control LEDs and report rpms/temps to motherboard): they'd even operate properly on ancient USB1.x ports (if you still could find any, lol).

USB3 header pinouts are electrically different but fully backwards-compatible with USB2, same overall concept but with USB3 "Y-splitter" adapters. USB3 controllers only provide USB3 power (900mA) and USB3 performance ("Super Speed" up to 5Gbps=625MB/s) on USB3-compliant hubs/devices which make use of all the additional electrical pins. A powered USB3 hub works the same way as a powered USB2 hub except that it will support faster USB3 speeds on all "downstream" connected USB devices. Same idea again with USB3.1 Gen 1, USB3.1 Gen 2, etc, except (as always) the USB electrical adapters/connectors are a bit different and maximum performance limits are bottlenecked by any component on the chain which isn't fully compliant with the newer/faster USB3 standard.
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[/Korth]

I had the same limitation issue with my build, where I needed far more USB 2.0 support than was available on the board.

In my case, I needed 1x for my Corsair H115i, 1x for my Corsair AX860i PSU, and 1x for my front panel USB 2.0 ports.
I ended up getting the NZXT interal USB hub that others in this thread have mentioned, and it is working out great.
I got mine through a seller on NewEgg, link below:

https://www.newegg.com/Product/Product.aspx?Item=9SIA6KX5DC5917&cm_re=nzxt_usb_internal-_-17-116-035...

It mounts magnetically, although admittedly weak, and uses a 4-pin molex connector for power so it isn't drawing too much from the header on the board.

Definitely suggest this for anyone who needs more than 1 USB 2.0 internal header.

Asryan
Level 10
Hi

Is there the equivalent of this hub but without a molex? ...