Power supplied by PCI-express?

miniyazz · 22 Nov 2009 at 02:09

My Google-Fu is weakening as the night progresses.. anyway, I have a couple of 8600GTSs and am looking to get another graphics card, but only have one PCI-e x16 slot (mobo is Asus P5Q Pro). I know I can run a (x16) graphics card in a x1 slot; unfortunately (according to wiki) my current cards each take 75W through their x16 slots which, my memory tells me, is the power limit for x16 slots - and having tried one of them in a PCI-e x1 slot, can confirm that x1 does not provide sufficient power to run the card (no external power connector

)

So what I was wondering is.. how much power can a PCI-e x1 slot provide? Does it increase with PCI-e 2.0? And.. does it interfere with data transfer (i.e. throttle bandwidth further)?

Basically I want to know how power-hungry a card I can get that will still run in a x1 slot; if it has a 6-pin external power connector, that can presumably 'take' 75W from the card's TDP, so the x1 slot only has to cope with the power drain over 75W.

Any help appreciated!

Cheers

miniyazz · 22 Nov 2009 at 11:15

My Google-Fu is strengthening

25W for PCI-E x1, 4 and 8 (but only 10W at startup for x1).

hairydave · 22 Nov 2009 at 11:16

Im not sure but if your going to run a card that needs external power through a x1 slot I imagine that the bandwith will be crippled.

PCI Express x1 = 250 MB/s or 500MB/s (PCIe2.0).

What are you using these cards for? Would it not make more sense to consolidate with 1 more poerful card? GTX260's are quite good value now.

miniyazz · 22 Nov 2009 at 11:23

hairydave said:
Im not sure but if your going to run a card that needs external power through a x1 slot I imagine that the bandwith will be crippled.

PCI Express x1 = 250 MB/s or 500MB/s (PCIe2.0).

What are you using these cards for? Would it not make more sense to consolidate with 1 more poerful card? GTX260's are quite good value now.

The third will be just for folding@home; 250MB/s should be plenty for even a decent card I think. I'm just hoping to pick something up for peanuts really though, and if it needs too much power I'll just sell an 8600 I guess!