Bitcoin Forum

Hello everyone!

I started mining WDC a couple of months ago with my gaming PC, then got caught in the game. I bought a mining rig a couple of weeks ago:

Asrock 970 Extreme4
AMD Sempron 145
2x2GB Hynix DDR3
3x Asus R9 280X DCU2 Top
Win 7 64-bit.

It is working great (about 720kh/s each) until I bought a fourth GPU. I decided to get 4 powered risers (PCIe 1x to 16x). When I use those, only one GPU is recognized, on the PCIe5 connector with a lower hashrate (600kh/s). And sometimes the fan of the GPU in the PCIe1 connector do not spin. I tried several connectors, and the only difference I had was a totally black screen.

All the GPUs are working fine if they are connected directly on the PCIe 16x connectors, but there are only three of those and heat is an issue.

Did anyone had this issue before?

Also, I don't know if it is relevant, but the powered risers have only a +12V molex connector, without Ground.

Thank you and Happy New Year!!!  ;)

Hi nnay_th,

Have you been to this site: http://www.cryptobadger.com/2013/04/build-a-litecoin-mining-rig-windows/.
I been looking forward to build the same rig, hope this site can help. Happy new year.

You might need pin shorting: https://bitcointalk.org/index.php?topic=36061.0

What psu are you using?

Hi suzanneg,

This is exactly where I got my info about building a rig! Best tutorial I could find so far!  ;D
The difference is that I intend to use 4 GPUs with 4 powered PCIe 1x to 16x risers.


Hi cryptoprime,

Yes I'm considering doing this, but I can't find info from owners of the same mobo.

Do you know if I can safely short a PCI x16 slot? I found infos about shorting a 1x slot, but nothing about the 16x slots.

Also I read stories from people frying their mobo shortly after shorting their PCIe ports... simply horrifying..  :o


Hi justkid,

I have two Akasa Cobra 850w running on the same rig, which are intended to power two GPUs each. With a total of 1700w, I think that might not be the issue.

i had some what the some problem with my first rig evga x58 ftw3, i had to get 16x riser on the 3 pci e and one power 4 pin on my four card and i wouldnt get 100% on my 3rd and 4th card, so i ratter keep my rigs at 3 cards.

you could always get your self some use parts on ebay to run an extra card or 2 , did it my self got my self a dual pci e board for 50 bucks on ebay
and i was able to run 3 cards on it.

Maybe one of powered riser's is damaged?
I dont know for sure, but a PCI x1 slot just got about 500Mb/s in each direction and my solo mining gpu produces a heavy amount of traffic. when start copying files between 2 harddrive's while mining, i just got half the i normally got.
So maybe a PCI 2.0 1x slot hasn't enough bandwith to fuel a HD7970/R280X ???

well that would really be the last thing I would do, since I know people are successfully using 5 GPUs on an Asrock 970 Ex4, but I'm starting considering it at least temporary, just the time it takes to solve this matter as I don't like having an extra GPU sitting there idling.


Well I have 5 PCI risers, and I tried to use only one at a time while the three other GPUs are connected directly to the mobo. The ones on the mobo are detected, but not the one on the riser. I tried each riser, unsuccessfully.

I even tried to short the presence pins, but no change...

I have the same problem. I have 5 of these boards and on all of them i cant get 4 gpus to work on x1-x16 powered risers.

hi Thomza,

were you able to run at least one GPU with a powered riser?

I have talked to my PCIE riser supplier (a really great guy), he told me that he always has problems with this particular mobo and powered risers.

I'm considering getting another motherboard, but I need to make more research. I want to find the sweet mobo that will take 4 GPUs on powered risers no question asked.

I can get 2 on risers at most. One in the first x16 slot and one in last x1 slot and one directly on the board. Didnt yet try all the combinations but at least im running 3 of them for now. I can run 4 gpus on ASUS M5A97 R2.0 without any problems.

Good to know for the ASUS M5A97 R2.0! Are all your 4 gpus on powered riser on this one? If so, are they 1x to 16x risers or 16x to 16x?

Thanks mate!  ;D

All powered x1-x16 risers on r9 290s

Just ordered my ASUS M5A97 LE, I'll let you know.

I keep my fingers crossed  :)

I got them to work now. It turned out i had a few defected risers. All of my asrock boards now work with risers on pce1, pcie2, pcie3, pcie5. Don't know whats why it doesn't work on pcie4.

You should be very very careful with those powered x1-x16 risers ... These are no extra-quality cables, but merely quick&dirty china-hand-made cables. They requires very gentle handling - you shouldn't do any rolling or bending of the cables otherwise the cable and/or power connector might detach from the "extension slot". And one other thing to be very careful with x1-x16 risers -> if you are putting them into x16 slot you can easily insert it in the wrong direction - in this case it will burn the riser and if you are unlucky it might even burn the PCIe slot or the GPU. So, careful when using those risers!

I had ordered kind of good risers, but as i found it out lately, they were wrongly done, and i got burned my MB and risers.

Great news! Have you tried shorting the PCIE4?

no and i dont intend to...

So, I got an Asus M5A97 LE R2.0. The good news is that I can get two GPUs to work in the two PCIe 16x slots with 1x to 16x risers... And apparently, I also have two faulty risers as they do not seem to work in those slots...

The bad news is that I can't get the risers to work in the PCIe 1x slots... And I'll have to RMA the M5A97 as the first PCIe 1x is missing a pin...

Well, it's better but still bad luck... I also have a GPU to RMA as it generates a LOT of vibration...

Asus, Asus, what are you becoming??  :-[

Hi, does someone knows where I can find instructions to make powered risers out from not powered? (just by DIY :)
Here in Europe I had no luck to find a supplier for powered risers, only for normal (not powered) 1x and 16x.
But I guess it should not be too difficult to make a powered one out from a normal one...?

Cheers, BitWalker

sorry for noob question, guys

i'm looking to build a rig,
so i decided to buy:

MB asrock 970 extreme 4
cpu sempron 145
4gb ram g. skill dual channel 1333 mhz
5 sapphire R9 280x Toxic
2 PSU aerocool strike-x 1100w (1 for 3 cards and other for 2 cards and mobo)

i would to run this rig with linux, (bamt maybe) but i never use it, if anyone have some tips about this issue thanks in advance.

the question:

asrok 970 have 3 pci-e 16x slots and 2 pci-e 1x solts. i have to use all slots.
i found risers obviusly in china, and it seems products are good, but all risers are unpowered.

now, what difference in khash/s terms can be happened with non powered riser cable versus powered?
it is better  to buy only powered? or non powered 16x and powered 1x?

why we need powered risers if cards are alredy powered directly by PSU?

tnx for reply :)

i solved my question by myself, and i post for other guys have same dubt.

graphic cards like R9 280x toxic, have two 8pin  power bouts, and it supplies 150w each one.
the card, is tested at maxymum consumtion of about 370w but on 3d games and at max overclock,  think for mining the consumption will be lowest, and 300w directly supplies by PSU are more than adeguate. so i think unpowered risers are good for this rig.

edit for info:
6 pin bouts, supplies 75w each
8 pin bouts, supplies 150w each
molex supplies 75w
PCI-E 16x slot supplies 75w
PCI-E 1x solt supplies 75w  (not sure for that info, i'm trying to find better info).

Hi BitWalker,

Try this tutorial:

http://forum.feathercoin.com/index.php?topic=2193.0 (http://forum.feathercoin.com/index.php?topic=2193.0)

Hope it helps.

Otherwise I live in UK and finding powered risers is relatively easy on eBay.

Cheers

Hi,

Wow, hold on a sec before you fry your motherboard! Even if you can get up to 300w via 8-pin, the graphics cards will still pull power from the PCIe slots.

From what I read, it is not recommended to use more that three unpowered risers. In your configuration, I would personally recommend at least 2 powered risers and three unpowered ones. But it doesn't hurt to have only powered ones.

Hope I saved you some trouble  ;D

ty for advice :)

i'm going to order risers next tuesday, so, for make no mistake, better if i order powered risers. :)