PCIe riser cards (powered?).

[SFF EOL]

I’m a bit confused about PCIE riser cards, I picked up that some are powered with a Molex and some (most?) are not. I just ordered a powered one, from Germany which will probably not work as really it will be China.


Anyway why do they need to be powered? Surely the PCIE cable will supply the power from the PCIE socket or the card will be getting its own supply direct from the PSU?

 

[Hellow]

More long is the cable less powerful is the signal

 

[SFF EOL]

More long is the cable less powerful is the signal

Didn't realise it would be that dramatic. I bought a Palit 1050ti passive, without realising the size of the thing, so I need a riser now. Live and learn.

 

[Valantar]

The main reason for powered risers is kind of twofold, AFAIK: the difficulty of including a thick enough conductor in the riser ribbon to transfer 5-6A@12V without some serious heat (riser ribbon cable wires are 24AWG or similar gauges, which is low for that kind of power), and for compatibility with motherboards that don't provide the full 75W to the x16 slot (applies to a lot of pre-built SFF boards). Also, of course, a lot of risers were designed for mining, when you'd connect at least 3-4 GPUs to the motherboard, which is far too much power for the motherboard to deliver without help.