Hey everyone, I'm new to the forum and just wanted to share some issues I'm having with my first custom-built PC. I bought this setup from someone through a friend and it was performing well initially. However, after moving it to my apartment, the RTX 3080 card failed, so I replaced it with an Asus RTX 5070 12GB. I made sure to connect it correctly using two 8-pin connectors from different power ports. Now, while my games are running, the performance is way below expectations, with low and fluctuating FPS. For example, Rust is only hitting around 70 FPS, and other shooters are barely reaching 110-120 FPS even with mild GPU usage. I've gone through a bunch of troubleshooting steps, including DDU, reinstalling drivers, optimizing both Nvidia settings and in-game options, and even a fresh Windows install. Nothing seems to help! My CPU usage is showing a maximum of 15%, indicating a possible bottleneck. It's frustrating because I thought I'd built a solid rig. Any advice before I consider returning the GPU or parting out my build? Here are the specs if that helps: AMD Ryzen 9 3900, 32GB RAM, Asus TUF X570-Plus Gaming motherboard, Samsung 970 EVO Plus 1TB SSD, and a be quiet! Power Zone 850W PSU. Any guidance would be appreciated!
3 Answers
You likely have a CPU limitation. That 15% CPU usage is averaged across all cores, but in most cases, games are only utilizing 1 or 2 cores effectively. Check in Task Manager under the CPU performance tab, select to view logical processors, and see if some cores are maxed out while others aren’t really doing much at all. By the way, when you adjust graphics settings, your GPU usage does change, right? That could help pinpoint the issue.
Your CPU is a bit outdated for gaming, especially when you consider how many cores it has. The Ryzen 9 3900 has two 6-core chips bonded together, meaning there can be latency when a game needs to communicate across those two sets. This often leads to lower performance. The low overall CPU utilization you see is likely because most games don’t use all those cores, which means a lot of them sit idle. A good test is to drop your game’s resolution—a notable improvement in FPS could confirm a CPU bottleneck.
Thanks for your insights! I tried dropping the resolution from 1920x1080 down to as low as 800x600, and the FPS remained pretty much unchanged. It seems to only spike during menus or less demanding scenes.
You might be running into a CPU bottleneck here. The Ryzen 9 3900 is decent, but it's possible it's struggling to keep up with that 5070 GPU. Keep an eye on your GPU usage; if it’s hitting much less than 100%, it could explain the low FPS. If you're looking for an upgrade, consider the Ryzen 5700X3D if it fits your budget. Here's a link for more info on bottlenecks: [link](https://www.pcworld.com/article/1955495/pc-bottlenecks-cpu-or-cpu-limiting-gaming-performance.html).
I get that, but how can that large performance gap between what you expect from the 5070 and the actual 70 FPS be just from a bottleneck?
Thanks for the fast response! I noticed that when I switch between low and high graphics, the GPU use goes up, but FPS only increases by about 15 FPS. When checking the CPU graphs, I see Processor 2 at 100% and others sitting between 30% to 50%. What's up with that?