With the warmer months ahead of us, I though it would be a good time to discuss keeping your cards cooler and hashing properly. I have seen many miners struggle with this and as I have a small farm at home and also managed a larger farm of over 100 GPUs this is an issue many people can run into. I have been able to keep my cards around 40-60 degrees Celsius depending on the day without the need of AC.
Replacing Thermal Paste:
Replacing thermal paste on a card will drop the core temps of the GPU and is recommended to be done every 4 years, as the original thermal paste will become crusty. Crusty thermal paste does not transfer the heat from the dye to the heat sync as efficiently as fresh, new thermal paste. Make sure when removing the old paste, you use Isopropyl alcohol. This will make sure the GPU dye gets cleaned and any oil or grease is removed from the surface before applying new paste. You will also want to clean off the heat sync the same way. When applying new thermal paste make sure you use GPUz and verify the hotspot temperature and the dye temp has a difference of less than 15-20 degress Celsius. Keeping the core temps low will also help lower memory temps, as the heat from the dye is transferred more efficiently, the amount of heat soaking out to the dye to the PCB is lowered.
What thermal paste to use:
There are many options for thermal paste to use. I will list my top 3 here, almost any aftermarket thermal paste will be better than the paste applied at the factory.
The SYY 157 thermal paste is carbon based and what I have switched over to recently. The paste is harder to apply as you do not spread it because of the consistency, but will create a very thin layer for improved heat transfer. This thermal paste has a heat transfer of 15.7 W/m.k and is $7.77 for 2 grams.
Thermal Grizzly Kryonaut is also a good choice. It is more expensive being $6.99 for 1 gram of thermal paste but is easier to apply. This paste has a heat transfer of 12.5 w/m.k.
The Artic MX-5 Thermal paste is also a good buy. You can get a tube of 4 grams for $14.99 with a heat transfer of 5W/m.k. Many miners use this thermal paste due to it being on the market for so long and proving it can last a significant amount of time under these conditions.
Replacing Thermal Pads:
Replacing thermal pads is extremely important for GPU mining. As algorithms like Ethash mostly use the GPUs memory. Most higher end cards will have memory temp sensors and even most mid grade AMD cards. Generally getting around 80-90c is where miners end up, even after replacing thermal pads. You don't want the memory temp to be sitting around 100-110 for long periods of time, as this can cause the GPU to thermal throttle and reduce the life expectancy of the card. There are many brands of thermal pads, but again almost any brand will be better than the stock thermal pads. Here are my top choices for thermal pads.
The Thermal Grizzly Thermal pads are what I mainly use. As these pads have not leaked oil as much as the other pads I have seen and have good thermal transfer. The Minus pad 8 is around 8W/m.k and these are fairly expensive.
The Thermalright pads also do a good job. I have had some luck with these as they have a better heat transfer but tend to leak a bit more.
External Cooling Fans:
If you are running your GPUs inside of server cases, then you most likely have high RPM fans already. From my testing in open air rigs and server cases it is best to have the fans pushing air to the GPUs rather than having them try to pull the hot air away. I believe this works better because you are pushing cooler air to the card and also increasing the CFM, forcing the warmer air to move away at the same time. If possible have a external box fan that pushes the air from the back of the rigs away to help prevent heat building up in 1 area. In order the keep the cost of building rigs down, I did cheap out on the fans. I'll link a few recommendations below but for long term use, getting fans with magnetic bearings will prevent the need to replace them. This will also keep the sound generated by the fans lower.
PCCooler has some cheap fans you can use for mining.. These cost $11.99 for a pack of three. Generally any cheap fans will do the trick. I would highly recommend looking for fans with rubber on the mounting points just to help keep noise low.
Noctua is still the golden standard of fans. They tend to push a lot of air while being extremely quiet. These fans cost a lot more at $31.90 per fan.
Corsair ML120 Magnetic Levitation fans are what I plan on switching to in the future. These fans are fairly expensive, especially if you opt in for the RGB fans. A 2 pack is $42.36, but the bearings will last an extremely long time and also have reduced noise.
If you have replaced thermal pads, thermal paste and have a good air flow set up but still have some cards running hot then there are two other things you can do. The first is to space your GPUs out more. The second solution is to add more surface area for cooling the GPU. This is easy to do as there are many options for heat syncs out there. I will link the few I have used and explain which one you should get depending on your use case.
The Easycargo 100pcs Heatsink kit works great for GPUs that do not have a backplate. Because of the uneven surface this kit works wonders. Just make sure you buy the pack that comes with Pre-applied thermal tape. Also make sure you use the taller heat syncs towards the center of the GPU so that the air blowing past the heatsinks can hit these. This kit only costs $14.99 for 100 pieces with the tape pre-applied.
The Easycargo 10pcs 20mm Kit works well for cards with backplates. These are usually short enough to fit in your rig and are great for placing just on top of the backplate where the memory modules are. In this kit you get 10 20x20x10mm pieces for $11.99.
Smaller steps that can be taken:
If you don't have the time or money to purchase fans, heat syncs, thermal paste or pads there are a few things you can do. The best thing you can do is insure you have adequate space between your GPUs. You can also ramp up the stock fans, for long term use I wouldn't recommend going above 80% fan speed. You could also turn off the RGB on the cards, typically the LED's are located on the plastic shroud around the fans and generate some extra heat. You could also move your rig closer to the ground, as hot air rises. I also have an overclocking article here. You can decrease the power limit to help keep the temps down as well.