I've been mining for over a year with 12 GPUs, so I can share what's worked for me:

Room Ventilation

The most important thing is to create a proper airflow path. You need both intake and exhaust. I installed a 240mm exhaust fan in the wall that vents directly outside, and I keep a window cracked on the opposite side of the room for fresh air intake. This creates a constant flow of air through the room.

Rig Positioning

Make sure your rigs aren't too close together. I keep mine at least 2 feet apart to prevent hot air from one rig heating up another.

Fan Configuration

Box fans work, but they're not very efficient. I use 120mm server fans (Delta brand) mounted directly to my mining frames. They move a lot more air and are more reliable, though they can be noisy.

Thermal Pads

For RX 580s, replacing the stock thermal pads with Gelid GP-Extreme made a 5-8°C difference for me. Definitely worth it.

Immersion cooling is effective but expensive and messy for home miners. I wouldn't recommend it unless you're running 50+ GPUs.

One cost-effective solution I've found is using a grow tent. They're designed for indoor plant growing but work perfectly for mining:

• They're relatively cheap ($80-150 depending on size)
• They're designed to be sealed with ventilation ports
• You can mount exhaust fans directly to the ventilation ports
• They contain all the heat and noise in one space

I have a 4x4 tent with two 6-inch inline duct fans (one intake, one exhaust) connected to flexible ducting. The exhaust goes directly out a window. My temps stay below 65°C even with 6 GPUs in the tent.

Another tip: undervolt your GPUs. My RX 580s run at 950mV instead of the stock 1150mV. This reduced temperatures by about 10°C with only a 3% hashrate loss.

Thanks for the suggestions! The grow tent idea is really interesting, I hadn't thought of that.

@HardwarePro - What model of Delta fans are you using? And did you wire them directly to the PSU or are you using a controller?

@EcoMiner - I'm already undervolting, but not as aggressively as you. I'll try pushing it a bit further. What software are you using for the AMD cards?

@CoolMiner - I'm using Delta PFC1212DE fans. They're 120mm server fans with very high static pressure, which is good for pushing air through densely packed rigs. They're 12V and I have them connected to a fan hub that's powered by a SATA connector from the PSU.

Word of warning though - these fans are LOUD. Like, vacuum cleaner loud. If noise is a concern, you might want to look at Noctua industrial fans instead. They move less air but are much quieter.

Another option is to use an AC Infinity CLOUDLINE duct fan. They're designed for grow tents as @EcoMiner mentioned, but they have speed controllers and are relatively quiet for the amount of air they move.

@CoolMiner - For AMD cards I use OverdriveNTool. It's much better than Wattman for mining because you can save profiles and apply them easily. For my RX 580s, I use these settings:

Core Clock: 1150 MHz
Core Voltage: 950 mV
Memory Clock: 2150 MHz
Memory Voltage: 850 mV
Fan Speed: 65% fixed
Power Limit: -20%
                    

This gives me about 30.5 MH/s on Ethereum (which is similar to Equihash for cooling purposes) while keeping temps around 62°C with good airflow.

One more cooling tip: If you're using open-air frames, mount a box fan horizontally ABOVE the rig, blowing upward. Hot air rises naturally, and this helps extract it more efficiently than fans blowing across the cards.

I'll add my two cents on cooling solutions:

For a budget option, I've had success with the "box fan + air filter" approach. I buy cheap 20" box fans and tape HVAC filters to the intake side. This serves two purposes:

1. It keeps dust out of your mining rigs (a major cause of heat buildup over time)
2. It creates positive pressure in the room if you have enough fans, pushing hot air out through any cracks/openings

For more permanent setups, consider a mini-split AC unit. They're more energy efficient than window units and can be installed in rooms without windows. The initial cost is higher ($700-1500 installed), but they're quiet and effective.

Regarding thermal pads: I've found that Arctic MX-4 thermal paste combined with Thermal Grizzly Minus Pad 8 thermal pads work extremely well for GPU refreshes. Just be sure to get the right thickness for your specific card model.