Bitcoin Forum

Since I can't post in the alternative currencies section I am wondering if someone can post this there on my behalf.

I recently went from two GPU's to four GPU's on the same mining rig. I am running into a problem where only 2 of my workers are connecting at once. My computer does detect all four GPU's and I can use any combination of 2, but when I try to get the third and fourth one, it just says connection problems. I am doing reaper, I tried stratum but I can't get it to work. I must be doing something wrong, I just don't grasp the concept I guess. My OS is Windows 7. I have 4 7950's and a 1200w PS.

So I have my workers on 0-0 tahiti, 0-1 tahiti, 0-2 tahiti and 0-3 tahiti.

Any help is much appreciated.

Hi,

Please post your current reaper parameters and I will look at them and advise...

Keiichicom

Thread Concurency - 21712
work size 256
intensity 20
Vectors 1
GPU threads 1

Hi,


Try dropping your thread concurrency; it might be too high, other settings look fine.  if this doesn't work drop your intensity until all gpu's connect. If this still doesn't work or it doesn't mine fast enough for you, then you could try cgminer instead, I found it a bit easier to tweak (although I admit I only have one gpu...)


Cheers, Keiichicom.

Thanks, I'll try that, What should I lower the thread concurrency to?

Now I can't connect with any. Not sure what to do.

Hi,

I am not sure but what I do know is that the higher the thread concurrency the more ram memory it uses on your gpu, so you need to drop it so that you aren't using up the gpu's memory.

This thread might help:



Keiichicom.https://bitcointalk.org/index.php?topic=176871.0 (https://bitcointalk.org/index.php?topic=176871.0)

Care to try cgminer, I have had trouble with reaper myself?

I was going to suggest that you need to increase system RAM as well.  I noticed that for LTC mining it generally works better when you have equal amounts of GPU memory and system RAM.  Not enough system RAM and the mining doesn't go well or at all.  Could be any number of things, but I might start there.  How much system RAM do you currently have?

I have 4 GB of RAM

I have seen the suggested RAM amount for LTC frequently cited as 1.5 GB RAM for each memory card in the 7xxx series. It sounds like you may need another 2 GB RAM to optimize your performance.

Ok well I will give that a try. I have an extra 4GB in my other PC. Thanks.

I managed to get 3 working. But when I try the fourth, my screen flickers black and it says "display drivers stopped responding and has recovered" it's always the same card. Anyone know what is going on?

The computer knows the card is there, it just says that every time I try to use it with this program.

You could try using cgminer instead, he seem's more stable and faster than reaper. I got my 7950's running at 650khash/s with cgminer and thread concurrency of  20480.

What intensity are you at?

Yes, use cgminer, it quadrupled my hashrate

Seems to have worked, thanks!

is cgminer pretty well always faster than reaper?  I just setup a rig with 4 7950s pulling 600 khash when overclocked 1500/1050