Do DLSS, FSR, and Frame Generation Cause PC Bottlenecks?

The Difference Between Upscaling and Frame Generation

To understand how these technologies affect your PC's balance, you first have to understand that "DLSS" and "FSR" are umbrella terms that cover two entirely different technologies: Upscaling and Frame Generation. They interact with your CPU and GPU in opposite ways.

What is Upscaling? (DLSS 2 / FSR 2)

Upscaling takes a game and renders it internally at a lower resolution (like 1080p). Because 1080p is easy to run, your frame rate skyrockets. Then, it uses a smart algorithm to stretch and sharpen that image to fit your actual monitor's resolution (like 4K) before displaying it to you.

What is Frame Generation? (DLSS 3 / FSR 3)

Frame Generation does not change the resolution. Instead, the graphics card looks at two fully rendered frames (Frame A and Frame B), uses AI to guess what happened between them, and inserts a fake, generated frame right in the middle. It visually doubles your frame rate.

How Upscaling Creates a CPU Bottleneck

Because upscaling (DLSS 2 / FSR 2) lowers the internal resolution, it makes the game incredibly easy for the GPU to run. This sounds great, until you remember the golden rule of resolution: Lowering the resolution shifts the burden to the CPU.

Imagine you are playing Cyberpunk 2077 at native 4K. Your GPU is struggling to hit 40 FPS. Your CPU is relaxing, easily preparing 40 frames per second. You are heavily GPU bottlenecked (which is normal and fine).

You turn on DLSS "Performance" mode. The game is now rendering internally at 1080p. Suddenly, your GPU can render 120 FPS. It turns to the CPU and demands 120 frames of game logic per second.

If you have an older or mid-range processor, it might only be capable of preparing 80 frames per second in Cyberpunk. The CPU immediately hits 100% utilization. Your GPU usage drops from 100% down to 70%.

The result: You turned on DLSS hoping for 120 FPS, but you only got 80 FPS, and the game is now stuttering because you created a severe CPU bottleneck. Your processor simply cannot keep up with the sped-up graphics card.

When to use Upscaling:

You should only use upscaling if you are heavily GPU limited. If your CPU usage is already above 80% while gaming, turning on DLSS or FSR upscaling will likely push it to 100%, causing stutters.

How Frame Generation Fixes a CPU Bottleneck

Frame generation (DLSS 3 / FSR 3) was specifically invented to bypass the CPU entirely.

Let's go back to the Cyberpunk example. You are stuck at 80 FPS because your CPU is maxed out at 100%. No matter how fast your GPU is, you cannot get past 80 FPS because the CPU cannot process game logic any faster.

You turn on Frame Generation. The GPU takes those 80 real frames, guesses what happens between them, and generates 80 "fake" frames. You are now seeing 160 FPS on your screen.

But here is the magic: The CPU doesn't know about those extra 80 frames. It is still only preparing the original 80 frames per second. The CPU's workload hasn't increased at all.

The result: Frame generation allows you to visually break past a hard CPU bottleneck. It is currently the only software technology in existence that can double your frame rate when your processor is at 100% utilization.

The Catch with Frame Generation

While Frame Generation is incredible for bypassing CPU bottlenecks, it has two major drawbacks:

1. Input Latency: Because the GPU has to wait for Frame B to be rendered before it can generate the fake frame in the middle, it adds a slight delay to your mouse movements. It makes the game look smoother, but it doesn't make it feel more responsive. This is why it should never be used in competitive shooters like Valorant or CS:GO.
2. Base Frame Rate Requirement: Frame generation multiplies what is already there. If your base frame rate is 30 FPS, the generated frames will be based on sluggish, choppy data, resulting in visual artifacts and horrible input lag. You generally need a base frame rate of at least 60 FPS for Frame Generation to look and feel good.

Conclusion: The Ultimate Rule for DLSS and FSR

When you are adjusting settings in a modern game, follow this rule:

• If your GPU is at 99% usage, turn on DLSS/FSR Upscaling to give the graphics card a break and increase FPS.
• If your CPU is near 100% usage, do not turn on Upscaling. It will make the stuttering worse. Instead, turn on DLSS/FSR Frame Generation to visually increase the frame rate without stressing the processor.

If you are confused about whether your current hardware is heavily mismatched, use our Bottleneck Calculator to estimate your system's capabilities. If you need practical ways to lower your processor usage without relying on Frame Gen, read our guide on how to fix 100% CPU usage.

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