Finding a GPU that is sufficiently powerful today and is ready for the future can cost a lot.
And the pricing situation for new GPUs only worsens when you factor in crypto miners and their hunger for every new piece of hardware.
So, used GPUs can be quite enticing, as they cost significantly less than new ones. But if you don’t know what you are looking for, you can be left with a used cryptocurrency mining card.
Let’s see why you don’t want a used mining card and how to check if a GPU has been modified for mining.
Should You Buy a Used Crypto Mining GPU?
Every piece of silicone, whether it is a CPU or a GPU, has a limited lifespan. You can’t use a GPU forever—part of the reason why is that thermal damage to the GPU accumulates over time.
GPUs get hot when pushed hard. If the heat isn’t dissipated quickly, it can permanently damage the silicone. Therefore, manufacturers equip GPUs with cooling solutions.
But managing heat can only do so much.
Every GPU accumulates damage as time goes on, and the rate of GPU damage accelerates significantly if you use it 24/7 for stressful tasks—like crypto mining.
In other words, you don’t want a used crypto mining GPU because you might not get the performance that you are paying for. In serious cases, you can end up with a faulty piece or something on the verge of complete failure. Furthermore, miners often mod their GPUs for mining. For instance, they might have overclocked the card or flashed a new BIOS.
So, you need to make sure that if you are buying a used GPU, you aren’t buying a used mining one that has been modded.
1. Check the Hardware
The first thing to check is the hardware. GPUs produced specifically for mining have differences in their hardware profile. For instance, a mining GPU may not have any ports to output to a display. This is a clear sign that the GPU is not for gaming.
Next, check to see any oddities in the printed circuit board (PCB). Is there any discoloration? If a GPU experiences extreme temperatures for prolonged periods, the PCB can show discoloration.
Similarly, check to see if there is any residue on the board. Residue can indicate that the GPU has experienced a lot of stress under high temperatures.
Next, do you see any oil around the chips? Oil or residue around the GPU could indicate that thermal compounds are leaking onto the board. Once again, this is due to the conditions that mining GPUs experience.
Finally, take the GPU cooling solution apart and ensure that there is enough thermal compound on the chips. Lack of any thermal compound can mean that the GPU has been working for a long time with inadequate cooling.
So, make sure to check all of these issues before committing to a GPU. If you spot any oddities and suspect that the hardware is pointing to a mining GPU, you are better off finding another one.
2. Check the GPU BIOS
Miners often flash their GPUs with a new BIOS to optimize the mining performance of the card. These optimizations can include reducing memory timings, increasing memory clock speeds, undervolting the card to get better thermals, and making the overall processing faster.
The problem with a crypto mining BIOS is that it doesn’t work well for gaming. For instance, you might get reduced performance. In some cases, games may even fail to start. So, you need to check if your card has a modified BIOS. But this is easier said than done.
GPUs don’t have any built-in mechanism to track different BIOS versions that someone has flashed on their card. Instead, you can only see the current BIOS version of the card and see if it matches any known versions.
To check your GPU BIOS version:
- Download and install GPU-Z on your computer. Run it and get the BIOS version of your GPU.
- Next, compare the BIOS version to the ones in the Techpowerup VGA BIOS Database.
- If you find the BIOS version listed there, then you have a gaming BIOS. Otherwise, chances are quite high you are running a modified BIOS.
That said, this method of BIOS verification is not without its faults. It is possible that your GPU model isn’t listed in the database.
Do your due diligence here. Examine the hardware first and then focus on the software to see the full picture.
3. Run GPU Benchmarks
GPUs used for mining can have lower performance than non-mining cards. As cryptocurrency mining GPUs often run 24/7, they can have permanent damage, reducing their performance, sometimes beyond repair.
Run a benchmark test on your GPU, like Furmark, and compare the score to brand new ones on the internet.
If you see a big performance differential, your card might be damaged. This can be a sign that the previous owner might have used the card for mining.
That said, there may or may not be any significant performance difference, even if you are running a mining card. Mining cards don’t always have degraded performance, especially if there were used for a short period. Performance deficits become harder to detect if the GPU was used with adequate cooling but may also indicate that the secondhand GPU is good to go.
4. Check for Overclocking
Aside from hardware and software modifications, mining GPUs often have overclocked memory speeds. Overlocking the VRAM speed and GPU frequency can significantly boost the hash rate, meaning almost all miners overclock their GPUs.
Checking for overclocking is quite easy. First, download and install GPU-Z if you haven’t already. Run the program and note the clock speeds. Then, compare the clock speeds of your card with others on the internet.
Make sure you compare the speeds to the exact models, as GPU clock speeds can vary between different manufacturers.
Not All Cryptocurrency Mining Cards are Bad
If a mining card is modified and can’t be used for gaming, you have no option but to look elsewhere.
But if a mining card has a display output, no hardware damage, and a normal BIOS, you can likely use it for gaming without any issues.
So, if you can only get a used GPU that was previously used for crypto mining, go for it, but exercise caution and run through our GPU checklist first.