How does GPU mining work? Which graphics card is the most profitable?

Understanding GPU Mining Mechanics

1. GPU mining relies on the parallel processing architecture of graphics cards to perform cryptographic hash calculations required by proof-of-work blockchains.

2. Miners install specialized software such as T-Rex Miner or GMiner, which interfaces with the GPU’s compute units to execute hashing algorithms like Ethash, KawPow, or Octopus.

3. The GPU receives work packages from a mining pool or solo node, processes them using thousands of shader cores simultaneously, and returns candidate solutions.

4. Valid shares are submitted to the pool server; when a block is solved, rewards are distributed proportionally based on each miner’s contributed hashrate.

5. Memory bandwidth, VRAM capacity, and power efficiency directly influence how many hashes per second a GPU can sustain without thermal throttling or instability.

Key Hardware Metrics That Drive Profitability

1. Hashrate per watt determines how much computational output a card delivers relative to its electricity consumption — a critical factor in regions with high energy costs.

2. VRAM size and bandwidth affect compatibility with memory-hard algorithms; for example, Ethereum Classic’s Etchash requires at least 4GB of fast GDDR6 memory to avoid stale share generation.

3. Driver stability and firmware support impact uptime; older AMD cards sometimes suffer from inconsistent OpenCL performance under Linux-based mining rigs.

4. Thermal design influences long-term reliability; sustained 85°C+ operation degrades memory modules faster, especially on reference-cooled NVIDIA GTX 10-series models.

5. BIOS modding potential allows voltage/frequency tuning that can increase hashrate by 12–18% on compatible Radeon RX 580/570 units without proportional power spikes.

Top Performing GPUs in Current Market Conditions

1. AMD Radeon RX 6700 XT delivers ~47 MH/s on KawPow at ~110W, maintaining strong efficiency after Ethereum’s merge shifted focus toward alternative coins.

2. NVIDIA RTX 4070 Ti achieves ~52 MH/s on Octopus while consuming only 145W, making it one of the few modern cards profitable even under $0.08/kWh electricity rates.

3. AMD Radeon RX 6600 offers surprising value: ~38 MH/s on Autolykos2 with sub-80W draw, ideal for dense rack deployments where cooling and space are constrained.

4. Legacy cards like the RX 580 8GB remain widely deployed due to low acquisition cost and proven overclocking headroom, though their 150W+ idle-to-load delta reduces net margin over time.

5. The RTX 3090 still leads raw hashrate charts on certain algorithms but suffers from disproportionately high power use and scarcity-driven resale premiums that erode ROI.

Mining Pool Selection and Configuration Impact

1. Pools like 2Miners and Flypool enforce strict share validation rules; misconfigured clocks or unstable memory timings cause rapid rejection rates above 5%, slashing effective earnings.

2. Stratum V2 protocol adoption improves security and reduces latency, allowing faster propagation of new jobs — crucial for high-frequency algorithms like CuckooCycle variants.

3. Some pools apply dynamic fee structures tied to network difficulty; during sudden spikes in global hashrate, fees may rise from 1% to 2.5% without notice.

4. Geolocation-aware DNS routing minimizes round-trip time between GPU rig and pool server; rigs hosted in Frankfurt typically see 8–12ms lower latency than those connecting from São Paulo.

5. API access enables real-time monitoring of rejected shares, temperature thresholds, and fan speed logs — essential for preemptive hardware intervention before thermal shutdown occurs.

Frequently Asked Questions

Q: Can integrated graphics processors mine profitably?A: Integrated GPUs lack sufficient VRAM bandwidth and compute units to compete; even high-end APUs like the Ryzen 7 5700G produce less than 1 MH/s on most ASIC-resistant algorithms — insufficient to offset system overhead.

Q: Why do some miners disable CUDA cores on NVIDIA cards?A: Disabling unused CUDA partitions reduces power leakage and heat generation, allowing more stable memory overclocking — particularly effective on RTX 3060 Ti models running Ergo’s Autolykos2.

Q: Does VRAM type matter beyond capacity?A: Yes. GDDR6X chips found in RTX 3090 and RTX 4090 provide higher bandwidth per pin than standard GDDR6, enabling faster data fetches during memory-bound algorithm execution — measurable gains of 3–5% on Etchash.

Q: How does ambient temperature affect sustained hashrate?A: A 10°C increase in intake air temperature typically forces a 5–7% reduction in core clock to maintain thermal limits, directly lowering hashrate unless compensated via aggressive fan curves or liquid cooling.