I finally discovered why my PC was running poorly and the reason why kind off blew my mind

[Astro22]

My PC was underperforming and the reason why is not something I expected.

 

tl;dr: (But I recommend reading everything anyway)

Basically, my GPU was running on PCIe x2 speeds even though it was seated in an x16 slot and no other hardware limiting it.
The only reason I discovered this was because I noticed this small detail in GPU-Z.

 

I noticed that I wasn't getting the performance that I was used to. My PC has trouble performing like expected ever since I got it, but this time it was really noticeable.

In Red Dead Redemption 2 where I usually get above 60 fps at all times and often in the 70s, I was struggling to reach 50.

In Planet Coaster, at a reasonably small park where I used to get in the 80s now had trouble reaching even 30. This was the worst case.

Generally every game felt more sluggish than I was used to.

 

I tried so much like thinking my in-game setting were reset and trying to tinker with them again, reinstalling drivers and changing settings in Windows...
I even did a clean install of Windows entirely and it didn't fix anything.

 

It's this little line in GPU-Z that gave away the issue.

 

While it detected that the card was slotted in an x16 slot, the card was running at x2 which is shown after the @ sign that in the case of this picture is back at x16 since I fixed it.

It's possible that the card runs at x2 to save power when not under load but mine was constantly at x2 even under the most heavy loads I could put it in.

 

I decided to reseat the GPU and while I was at it, try to clean out any dust with a PC duster.
Sure enough in GPU-Z it stated that I was running at x16 speeds again and guess what.. All my games run perfectly fine again. Way smoother, way faster. Maybe even faster than before.

 

What completely blows me away is how an issue like this can drastically worsen your performance, yet there is not a single sign that there is an underlying problem.

I also never heard of this happening before.
Only when using software or other means to see what speeds your PCIe slot is running at, would you stumble upon it.

An average user would not discover this at all. With average I mean someone that doesn't really know that much about a computer. People on this sub would probably have a way higher chance of discovering this.

[Brian McKee]

It was likely not making perfect contact with the pins on the motherboard and thus making it seem like you were connected to a 2x pcie (which you can do by the way if the pcie slot is open ended).

 

This could have been dust, corrosion, or just not being seated correctly. But yes this is not an obvious diagnosis, but it likely doesn't happen often.