First Post: PCI-E extension cable question

[ieatyou!]

This is, as the title says, my first post (so go easy if im doing something wrong). Anyway, I'm working on a case mod that would require placing a GTX 275 both above my motherboard and in the opposite direction of a riser card. I'm 97% sure I'm going to need a flexible PCI-E extension cable (which I was surprised to hear they make...).
This thing: http://i84.photobucket.com/albums/k26/photonmoo/PCI_Express_X16_Flexi_Riser_Card_-_.jpg
Couple questions:

1. I haven't been able to find a PCIE 2.0 version of one yet, I know 1.0 doesn't bottleneck with a GTX 275, but lets just say it would let me sleep better at night should I need to swap in a much nastier card.
2. Am I going to have timing problems? Very spotty answers to this question online. And if I am, if i adjust timings, will I see a large performance delay?
3. Taking question 2 into account, how long a cable can I use?
4. I've seen some at Orbitmicro for 60, and on Ebay for 4.99, any suggested retailers?

Thanks, responses will earn my eternal gratitude :p

[DarkWhite]

I know one dude posted a link as to a site that sells those relatively cheap, and they have a lot of options, I'm sure they'd have a 2.0 version.
I can't find the link, but maybe someone who can will chime in.

[torin3]

I'm not sure if this is the one you are talking about, but they have a lot of options:

http://www.adexelec.com/pciexp.htm#PEXP8-RX1A

[ieatyou!]

Thanks guys,

Does anyone know about the timing "issue"?

[Moto7451]

1. It shouldn't really matter since you're just extending the slot and there are no other chips between the ends of the cable. The slot itself did not change between PCIe 1.0 and 2.0.

2. There will be more latency but it's not likely to affect the card negatively. In Crossfire or SLI, the drivers automatically manage different latencies as is. Especially in the case of SLI, several implementations of it have included two cards separated by a link between two chips on the motherboard providing PCIe lanes. Those solutions create more latency than longer traces should.

3. I'd suggest keeping it as short as possible. The problem is that the signals aren't designed to travel very far (maybe 12" total - traces + extension - in a worst case scenario). I'd say you shouldn't use more than a 6" extension cable.

[ieatyou!]

1. It shouldn't really matter since you're just extending the slot and there are no other chips between the ends of the cable. The slot itself did not change between PCIe 1.0 and 2.0.

2. There will be more latency but it's not likely to affect the card negatively. In Crossfire or SLI, the drivers automatically manage different latencies as is. Especially in the case of SLI, several implementations of it have included two cards separated by a link between two chips on the motherboard providing PCIe lanes. Those solutions create more latency than longer traces should.

3. I'd suggest keeping it as short as possible. The problem is that the signals aren't designed to travel very far (maybe 12" total - traces + extension - in a worst case scenario). I'd say you shouldn't use more than a 6" extension cable.


Thanks Alot. The cable wouldn't be over 3-4 inches. Does anyone have experience with these?