Updated: Oct 15, 2020
Configuration: Motherboard: Gigabyte B250 Fintech, CPU: Intel Pentium G4400 3.3 GHZ 3MB Cache LGA 1151, Ram: Corsair DDR4 2400 mhz 4GB, SSD: ADATA 128 GB, GPU: AMD Sapphire Nitro Rx580 8GB, PSU: Corsair HX 1200 Watts Platinum.
Setup: Sapphire Nitro Rx 580 8 gb cards (Hynix memory) are bios modded previously with only time strap changed. Copied 2:1750 to 2:2000(Hynix). Copy 1:1750 to1:2000 for Samsung memory. But now you don't need bios mod as Claymore 15 has built in feature. Using Claymore15 with strap 6. Each card hashing around 31 mh/s with 80 -85 watts. Remember to open Claymore as admin. Also mention full path to file "EthDcrMiner64.exe". On each card Core is underclocked to 1180 MHz and undervolted to 810 mv from default. Memory is overclocked and undervolted from default respectively: GPU1 2070 MHZ 840 mv, GPU2 2040 MHz 930 mv, GPU3 2060 MHz 880 mv, GPU4 2035 MHz 895mv. These settings varies with memory type, brand or even with same brand and memory. So decrease/increase parameters in steps 5 units and search for the sweet spot on your GPU. After each 5 units shift wait for 10-15 min to check it's stability. First decrease the core frequency in steps 5 units until it get crashed/hangs/fails then under-volt in steps 5 until it get crashed. Reducing core reduces the card wattage. Increasing memory frequency increases mh/s. First Increase memory in steps 5 until it get crashed then under-volt in steps 5 until it get crashed. Total power consumption is around 338 watts in Claymore. At the wall power consumption is around 565 watts.
I started mining first with gaming motherboard Asus Prime Z270 AR with AMD crossfire technology. Mining motherboards were not available at that time. In crossfire technology while mining the first GPU on the pcie slot 16x is always under full load and hotter than the other GPU's.
AMD Wattman GUI latest version is heavy and often hangs and not that user friendly as it used to be earlier. Use OverdriveNTool in calibrating your GPU's. With OverdriveNTool while mining you can change the parameters with ease. Until you get 100% stability in all your GPU's while mining this tool comes handy in changing parameters in no time. https://forums.guru3d.com/threads/overdriventool-tool-for-amd-gpus.416116/
People building mining rigs with 6+ GPU's with two three PSU's. But is it wise to do so? You should keep in mind portable design of the rig, flexibility, cable management, overall system stability. Also mining algorithm changes often with increase power requirements. Ethereum will be shifting to new algorithm ProgPow, which require more power per GPU. Also mining different coins in different algorithm has different power requirements. When you upgrade to latest GPU it will definitely have TDP more than your previous GPU's. So make sure your PSU can supply that much extra power. Always select PSU based on total TDP/Max power consumption of your hardware plus some spare watts. Considering these factors build rigs with GPU's not more than maximum pcie ports on your PSU. Always go for platinum category PSU for reliability and efficiency. I prefer using Corsair Platinum PSU. Always choose PSU considering the ripples and efficiency under full load condition.
Mining Background: I share my personal experience here building mining rigs covering some important point which is often overlooked. Whatever it takes miners will continue mining. I am Miner first then SPO (stake pool operator). Mining taught me practically the core aspects of blockchain and block creation. Getting my mining rigs ready once again for Eth DAG size to cross 4 gb. Eth DAG size wil reach 3.99 gb on 26 December 2020. Difficulty decreases. Waiting for ProgPow mining algorithm. Desperate to achieve number 32. At the same time mining for ADA to pledge.
I am into mining since late 2016. But early 2017 difficulty rosed exponentially due to asics and ultimately profits got reduced. Now very soon 4gb GPU's and asics are going to be obsolete. So there will be good opportunity for miners having GPU's with memory more than 4gb to make good profit for sometime. Also with the implementation of ProgPow algorithm, dominance of asics will be drastically reduced.
Consensus Mechanism: In the blockchain, the best consensus mechanism is the most debated topic today which resulted in the division of ethereum community. So is hybrid consensus mechanism the best solution? Both POW and POS has its own merits and demerits. POS or DPOS which will succeed?. Hold on to the future for new consensus mechanism to evolve. What do you think about the best consensus mechanism yet to come?