[Mashiro]

It is very highly unlikely if not even impossible for a GTX 1080 to be as slow as or even slower than any other card below it or older than it.

There are factors that can however affect the performance towards the bad site and leading to a similar effect: a) different hardware is bottlenecking the GPU, b) there is a problem with power delivery to the GPU that throttles the power, c) the GPU has thermal issues and gets heavily throttled to prevent overheating or burning up and d) incompatible or old hardware is used.

a) Imagine using a GTX 1080 with a i3 CPU. This won't go very well. The CPU will be at its limit almost instantly and therefore bottleneck the GPU. This in returns causes the GPU to wait a lot.... and not bring the full performance because it doesn't get the data from the CPU at the fast speed that it needs to process the data with full performance.

b) Usually if the PSU doesn't deliver enough power the system wouldn't boot up due to "no video/GPU" error. However depending in the GPU you might be actually able to start the computer and use it. As soon as you start doing graphic intensive tasks and have NOT ENOUGH juice to run them the GPU will do power throttle and simply hold back all performance due to lack of power.

c) Well, not much to explain here I guess. GPU is running to hot due to some issues. Bad coolers? Broken coolers maybe even? Thermal paste dried up... The GPU reaches its thermal throttle temperature and will lower its power input/output and performance to keep the temperatures as low as possible.

d) Well, that is a more complex thing. GTX 1080 is a powerful beast and a still more recent GPU. It needs PCIe 3.0 and while you can use it on PCIe 2.0 the performance will be horrible because of the lacking PCIe bandwidth with PCIe 2.0. This again causes issues that lead to performance throttle as the GPU doesn't get the data fast enough to be able to process it at full speed. And other issues might be incompatible chipsets on mainboards that simply can't handle such powerful cards.

Last but not least don't forget posible faults in the hardware of the computer. While they might not lead to the computer breaking they might cause performance and stability issues.

And what @LightDestory mentioned about drivers and etc is also absolutely correct and should be considered.


Despite all of this the GTX 1080 is however still faster at all tasks than the GTX 660 which by now is a very old card and wouldn't be able to run most things nowadays on high settings.

Here is a comparison of the two based on the reference models: https://gpu.userbenchmark.com/Compare/Nv...3603vs2162 (non Ti models).