Unable to mine in Windows with 2 GPUs

rpmx

I have a machine that's running Windows 10, with 2 AMD R9 290s, and I'm trying to use geth with 2 instances of ethminer, one for each card. I've also set up port forwarding for port 30303, and geth is allowed through Windows Firewall.

The binaries for geth and ethminer were downloaded from build.ethdev.com.

Whenever I try running ethminer, the first instance always runs normally, but then the second immediately gives me this error: "DAG generation failure. Reason: Permission denied". So I've never been able to get both cards mining at the same time.

I've tried
- reversing the order in which I start up each card
- using geth with --rpc, and alternatively, with --rpccorsdomain
- starting up the ethminers before geth
- running cmd as admininstrator (I imagine sudo might have worked if I had been using linux

Is there anything I can do to fix this? I'd appreciate any feedback.

geekhaven

Im not at that stage yet but might be worth turning of the DX 12 features in win 10. It might be chaining the cards together instead of keeping them seperate.

rpmx

Thanks, do you have a link to a page with instructions on doing that?

I did do a google search after I read your post, and what I found (disabling DX by tweaking some settings in AMD CCC) didn't work.

Daface

Use the - t x setting to set the number of GPU's

corsaro

I confirm. On windows7 too, using 2 GPUs you can use just one GPU.
If you launch a second instance of "ethminer" using "ethminer -G --opencl-device 1" you receive the error message: "DAG generation failure. Reason: Permission denied" even if launching it with full Administrator rights.

Is there a fix?

rpmx

Daface said:

Use the - t x setting to set the number of GPU's

Yes, that worked. Thanks!

corsaro said:

I confirm. On windows7 too, using 2 GPUs you can use just one GPU.
If you launch a second instance of "ethminer" using "ethminer -G --opencl-device 1" you receive the error message: "DAG generation failure. Reason: Permission denied" even if launching it with full Administrator rights.

Is there a fix?

There's a way to mine in ethminer where both GPUs are used by one instance of the program. It's by giving it the "ethminer -G -t 2" command.

But first, I would check the order in which your GPUs are detected by ethminer, by typing "ethminer --list-devices". If you have onboard graphics, hopefully it would appear last on the list, after the discrete graphics cards. That's because when you include the argument "-t 2" in the command, that tells the program to use the first 2 GPUs that it detects.

For me, initially the Intel graphics processor was listed first, and the GPUs, although appearing on the list as well, weren't recognized by ethminer at all. After trying a few things, I was only able to fix this by reinstalling, which thankfully worked.

realrover

Running just ethminer -G will pick up all GPUs under W7. I have 4 and all are working.

corsaro

ok, solved. thanks

geekhaven

As a note i found if your using different card architecture with the cards you need

-- opencl-device 1 --opencl-platform 1

this was hte only way I could get my laptop to mine using the Nvidia GPU. Otherwise it would always attempt to use the inbuilt intel.

Might help someone.

cdrize

Not to be daft, rpmx...but, you said you had to re-install to fix the order of your graphics cards. I have the same issue. What did you re-install to fix this?

cdrize

@rpmx, you indicate that you had to re-install to get the order of the cards to change (intel after the graphics cards). What did you have to re-install? I have the exact same issue. I just tried to re-install eth again and that didn't work.

Sorry if this post is a duplicate. It doesn't look like the last one posted.

cdrize

Not to be daft, rpmx...but, you said you had to re-install to fix the order of your graphics cards. I have the same issue. What did you re-install to fix this?

cdrize

@rpmx, you indicate that you had to re-install to get the order of the cards to change (intel after the graphics cards). What did you have to re-install? I have the exact same issue. I just tried to re-install eth again and that didn't work.

Sorry if this post is a duplicate. It doesn't look like the last one posted.

jleefly

how long it take to get ether with 2 x 290x ?

o0ragman0o

@jleefly, Currently you should be getting around 2 blocks/day.

rpmx

cdrize said:

@rpmx, you indicate that you had to re-install to get the order of the cards to change (intel after the graphics cards). What did you have to re-install? I have the exact same issue. I just tried to re-install eth again and that didn't work.

Sorry if this post is a duplicate. It doesn't look like the last one posted.

Apologies for the late reply, I haven't checked the forum in a few days.

I reinstalled the OS, which in my case is Windows. But by now you've probably fixed the problem yourself

If you run into this problem in the future though, there is another possible solution. I haven't had the opportunity to test it, but it worked for someone on reddit (skip to the last paragraph).

swdave

In case you want to mine with some combination of CPU/CUDA/OPENCL on the same PC. I came up with a solution. Download a hex file editor. Copy ethminer.exe to ethminer2.exe. Edit with hex editor and search for "full-" and you will see something like "full-R%u-%016llx" then change "full-" to "ful2-" and save it. Now each miner will have their own DAG file, ethminer -G for GPU and ethminer2 -C for CPU.

rpmx

Thanks, that sounds really interesting, and I wonder if it will also fix this "Permission denied" error that people get when they try mining with one ethminer instance per GPU.

farware

@swdave I'm wondering whether the hashrate is higher in that case. Thanks for posting your solution that's ingenious