Bitcoin Forum

Hello,

I am using GeForce 840M GPU and Cudaminer 2014-02-28 to mine litecoins.
I tried different configurations for the card but I always get maximum hash rate 40KH/s.

I am using Win7 64-bit with latest drivers from NVidia.

I tried the following settings:
cudaminer.exe -d 840M -o stratum+tcp://litecoinpool.org:8080 -O worker:pass
cudaminer.exe -d 840M -l T5x12 -o stratum+tcp://litecoinpool.org:8080 -O worker:pass
cudaminer.exe -d 840M -l T8x10 -o stratum+tcp://litecoinpool.org:8080 -O worker:pass

Am I doing something wrong here? or this is the maximum of the GeForce 840M card?

Thanks for your help.

https://litecoin.info/Mining_hardware_comparison
Here you can see the expected hashrate and optimal configs for diferent hardware.

You have done nothing wrong. Cudaminer automatically optimise the settings for your GPU. In this case, it should be the max it can go. Nvidia cards are not optimized for opencl computing. Cudaminer attempts to improve your hashrate by utilizing the cusscores in nvidia GPU. Mobile GPU are never optimized for mining as they need low power usage and low heat output. Mining on it would surely stress thus overheating it and shortening the lifespan.

Thanks guys for your reply.

@cellard,

I already visited this website several times but I couldn't find my card listed.

@ranochigo,

Do you mean that cudaminer is not optimized for "Scrypt" mining? as I tried it with GUI-Miner for bitcoin and I got 25-70MH/s depending on the pool.

No, most nvidia GPU aren't that efficient if compared to the AMD GPUs. Bitcoins and litecoins are completely different, they have different algorithm to calculate for blocks, scrypt in general is harder to calculate than Bitcoin. Cudaminer is pretty much the best you can get for a nvidia gpu.