Just like CPUs, modern GPUs can dynamically adjust their clock speeds based on temperature, power, and workload, which is why they can squeeze as much performance as they can without you having to ...
If your graphics card isn't quite as fast as it once was but you aren't quite ready to upgrade yet, there's a lot you can do to boost performance. From driver updates to settings tweaks, overclocking, ...
The vertical GPU mount is a thermal trap for 90% of PC configurations.