It Is All About BTC, LTC, ETH, DOGE, KAS mining as well as other alternative crypto currencies
If you want to mine GPU Coin with Nvidia GPUs you will need to use the cudaminer software miner. GPUC uses Scrypt-Adaptive-Nfactor and not the standard Scrypt algorithm, so you need to run cudaminer with the –algo=scrypt:2048 parameter and not just with –algo=scrypt. Do have in mind that you should see about half of the typical Scrypt hashrate you get when you start mining for GPU Coin and that is absolutely normal due to the different algorithm being used.
We have tested mining for GPU Coin with a GeForce GTX 750 Ti video card running at stock frequencies and got about 134 KHS hashrate, after overclocking we’ve managed to get up to about 146 KHS. The kernel configuration that we found to work best was T10x24 on the GTX 750 Ti and this is the command line parameters we’ve used to launch the miner:
cudaminer.exe --algo=scrypt:2048 -o stratum+tcp://east1.us.stratum.dedicatedpool.com:3367 -u yourworker.1 -p password -i 0 -l T10x20 -C 1 -H 2
Below you can download the latest version of cudaminer 2014-02-28 for Windows with BAT files ready with the settings for mining GPU Coin, so you just need to configure them with your pool settings and start mining. Note that the default settings are the best for mining with GTX 750 Ti graphics cards, so you might need to change the kernel to another one based on your GPU or just remove the line setting up the kernel to use the autotune feature.
– Download the latest CUDAminer 2014-02-28 Nvidia GPU mining software for Windows…
Today we have built a 6-card mining rig using Gigabyte GeForce GTX 750 Ti (N75TOC-2GI) video cards that are based on the latest Nvidia Maxwell architecture promising very good performance for mining with low power usage. Our own initial tests of the GeForce GTX 750 Ti as a single card for mining have shown very promising results as well, so we’ve decided to see what we can expect from a mining rig and put together 6 cards with PCI-E x1-x1 extenders on an AsRock H81 Pro BTC motherboard with Intel Celeron G1820 CPU and 4GB of RAM running Windows 7.
The result we’ve got from the 6-card mining rig for mining Scrypt with CUDAminer was a total of 1480 KHS as hashrate. Then after overclocking the video cards to the maximum stable result we managed to get (+135 MHz for the GPU and +610 MHz for the video memory) we’ve managed to increase the total hashrate to about 1615 KHS. We went as far as to increase the power target limit from the default 38.5W by modifying the video BIOS of the cards. With the modified video BIOS we have managed to get slightly more than 1700 KHS with a lot of extra power used by the whole system that made it not worth it the so little extra increase in the hashrate. Just to be sure that the x1-x1 PCI-E risers (not powered) might be the cause of slight performance drop we’ve replaced them with x1-x16 USB 3.0 powered extenders, though that did not change the performance we got from the cards.
The Gigabyte GeForce GTX 750 Ti video cards we used for the mining rig do have an external PCI-E power connector, however it seems that unlike AMD graphics with OpenCL, when using Nvidia-based GPUs with CUDA for mining the use of a x1 PCI-E lane to access the video card does introduce slight performance drop and if you multiply the 10-15 KHS less per card for a 6-card mining rig it is not so little. So it is important to know that if you are going to build a GTX 750 Ti-based mining rig you will be getting slightly lower hashrate if you are using PCI-E extenders as compared to what you will get with cards inserted in x16 PCI-E slot directly. Also there is some variation between cards in terms of the maximum overclock supported that results in different maximum frequencies that you can achieve, for example if one card is able to do +135/+700 MHz for the GPU/VRAM the second one could be maximum +100/+600. This means that in a 6-card mining rig you will need to either sync all of the cards and use the same lower settings for overclocking the GPUs to ensure they will run stable or to not have the settings synced and find the maximum for each of the cards.
Another interesting thing we have noticed is that while the use of T5x24 kernel for a single card with CUDAminer for best results, for a 6-card mining rig the use of T10x24 might sometimes provide slightly higher hashrate than T5x24, so you should try with both and see what works better in your individual case. Tomorrow we are going to be doing some more testing of the 6-card GTX 750 Ti mining rig that will be focused mostly on the power consumption as this is also a very important thing when talking about crypto currency mining.
The GeForce GTX 750 Ti series of graphics cards based no the new Nvidia Maxwell architecture have really captured the attention of crypto currency miners due to their good performance (hashrate) per watt. Nvidia is advertising these cards to have 60W TDP, however we have discovered that the actual TDP limit for the power target set in the video BIOS of these cards is 38.5W…
This made us dig into the matter a bit more in order to see how much power actually does a GeForce GTX 750 Ti draw from the motherboard (a reference GT 750 with no external PCI-E power connector). So we’ve attached a watt meter to the power line of an external PCI-E extender to see how much power is drawn by the GT 750 Ti card. The results we got were quite surprising, even though we knew that the default power consumption should fit in the 38.5W limit for the power target set in the BIOS. With the stock frequencies for the GPU and the video memory the GeForce GTX 750 Ti has shown to draw just about 28W ot power producing about 250 KHS hashrate for Scrypt mining. After getting the card overclocked to +135 MHz for the GPU and +650 MHz for the video memory the power consumption has risen a bit to about 34W average with a hashrate of about 300 KHS for Scrypt crypto mining.
So if you were calculating the power usage of GTX 750 Ti as 60W in order to see the ratio of hashrate per Watt of power, then you should rethink how you calculate it now. Note that this is the actual power that goes from the PSU to the video card, the real power consumption with a 80 Plus certified power supply that provides 90% efficiency for example would rise with 10% to about 30W (stock) and 37W (overclocked) respectively as the actual power drawn by the card from the wall socket.