Mining Rig -> GPU + Riser problem, help needed!

[Jsnow]

Hello to everyone!

First of all, I'm a noob in Mining and such, so I'm sorry if I'm asking something obvious for you.

That sayd, I've some problems with my mining rig, here my setup:

MB: Asrock 970 Extreme4
CPU: Sempron 145
PSU: Corsair AX860 Platinum
RAM: Gskill 1x4Gb 1333Mhz
SSD: Kingston 60Gb
GPU: 3x Sapphire R9 280x OC Dual-X 3GbGDDR5
Riser: 3x Powered Risers 1x-16x

I tested all the 3 cards and all the 3 risers in every combination, and all of the items are working good at 700-750 KH/s.


My problem is the following:

The PCIE4 slot, the 16x in the middle of the MB, is not recognizing any card if I use them with any of the risers -> D6 error on the Dr.Debug led on the MB, that is: "No console output devices are found".

I tested the same slot, the PCIE4 slot, plugging in any of the cards directly, without risers, and it recognizes them normally.
I also tested the 3 16x slots together, plugging all of the cards directly in, without the risers, and all of 3 works fine.
I tested the other 2 16x slots of the MB with risers, and they recognize the cards normally.

So, why that single slot isn't recognizing the 1x-16x risers? Should I need to buy a 16x-16x for that slot? There's a way to fix it somehow?



And also, I've encountered another probem trying to avoid using that 16x slot, here the configurations I've tried so far:

Config A:
GPU 0 -> Riser plugged in PCIE 16x slot --> 700Kh/s
GPU 1 -> Riser plugged in PCIE 16x slot --> 700KH/s
GPU 2 -> Riser plugged in PCIE 1x slot --> 100KH/s

Config B:
GPU 2 -> Riser plugged in PCIE 1x slot --> 700KH/s
GPU 1 -> Riser plugged in PCIE 1x slot --> 700KH/s
GPU 0 -> Riser plugged in PCIE 16x slot --> 100KH/s

So, with both those configurations, all of the 3 cards are correctly recognized with the risers.
BUT, in both cases, the single card that has a different PCIE Interface compared to the other 2 cards (GPU 2 in config A & GPU 0 in config B) is having a really low hash rate for some reasons.

Why?
I think this could be a setup problem and I hope that you could help me fixing it.


Thank you in advance to anyone that will try to help me out.

Jsnow

[baltimoreppc]

Try uninstall AMD Catalyst and Reinstall with latest beta version - I think it is 13.11 something like that and Latest SDK(2.9?)

it solve my unstable issue..

[durden21]

Have you tried this?

http://blog.zorinaq.com/images/pcie-short-photo.jpg
http://blog.zorinaq.com/images/pcie-short-schematic.png

Obviously, some mobos need it to recognize that a slot is occupied (more info here: http://blog.zorinaq.com/?e=42)

By the way, I've got the same PSU as yourself. Are you sure that it is adequate for three R9 280x?

Cheers

[RickJamesBTC]

Are they ribbon cable risers? Those don't have the presence short built in. The USB style ones like I sell do. To run the ribbon cable ones on some mobos you need that jumper.

[TookDk]

Have you tried this?




Obviously, some mobos need it to recognize that a slot is occupied (more info here: http://blog.zorinaq.com/?e=42)

By the way, I've got the same PSU as yourself. Are you sure that it is adequate for three R9 280x?

Cheers

I don't believe that the AX860 is a good choice for 3 x R9 280X, measured 1 x R9 280X (undervolted) with a current clamb, at full hashing the power was about 270W, that will be 810W in total, leaving 50W for everything else, you can properly squeeze 5-10% more of of the AX, but I would not recommend it, as the derating of the components will proberly lead to short life time of the PSU. I believe that the AX860 is a PSU you can have for many many years if you dont punish it too hard.