Understanding CPU Utilization

[leafry]

Hey everyone; first time posting here, so forgive any ignorance. I recently just built a gaming pc for the first time in a very long while. I went all out and got the best parts I could, including:

• i9-9900k
• 128GB DDR4 RAM
• Geforce GTX 2080ti

I'm a little confused about my CPU utilization though. I built the pc in parts, some items came earlier than others so I was able to use some spare parts to at least get it up and running. I played a few games with all the pieces except the GPU for a while. I had a spare GTX 970 I used in it's place. While playing many games, I maxed out the GPU but the CPU and RAM were at very low single digit numbers. I was also only using a 1920x1080 display.

 

When my 2080 came in, that's when things got weird. I used the 2080 on the same display. The GPU was using single digits for all games, for instance Ghost Recon Breakpoint. But the CPU jumped up to 40 - 50%. When I switched to a 4K monitor, all of the sudden my GPU is at 30% (which makes sense) but the CPU went back down to single digits. I'm just confused why the 1920x1080 display caused such a huge spike in CPU but that goes away as soon as I'm pushing 4K.

Edited June 10, 2020 by leafry
spelling

[Enderman]

Because the GPU doesn't have to work as hard for 1080p so the CPU becomes more of a bottleneck while the GPU pumps out frames easily.