A bottleneck happens when one component in your PC holds back the performance of another. The most common example is pairing a very powerful graphics card with a weak processor — the CPU cannot feed data to the GPU fast enough, leaving your expensive GPU underutilised. This calculator helps you identify whether your CPU and GPU are well matched, and how severe any bottleneck is.
Select your CPU, GPU, intended use case, and RAM below. The calculator will analyse the performance balance between your components and give you a clear bottleneck percentage with tailored recommendations.
Bottleneck Calculator
Choose your CPU and GPU from the dropdowns. Then select what you primarily use your PC for — this affects how much weight is given to CPU vs GPU performance in the analysis.
What Is a CPU Bottleneck?
A CPU bottleneck occurs when your processor cannot deliver data to your GPU fast enough to keep it fully occupied. This typically happens when you pair a high-end GPU (like an RTX 4090) with an older or low-end CPU (like an i3). The result is that your GPU sits waiting for work, leading to lower frame rates than the GPU is technically capable of delivering. CPU bottlenecks are most visible at lower resolutions like 1080p, where the GPU finishes rendering frames quickly and constantly needs new work from the CPU.
What Is a GPU Bottleneck?
A GPU bottleneck is the opposite — your processor is powerful enough to prepare and send data faster than the GPU can render it. This is actually the ideal situation for gaming, because it means your GPU is working at or near 100% capacity and is the primary limiting factor. GPU bottlenecks become more common as resolution increases (1440p, 4K) because rendering more pixels requires significantly more GPU power.
How Is the Bottleneck Percentage Calculated?
The bottleneck percentage represents the performance gap between your CPU and GPU, adjusted for your use case. Each component is assigned a performance score based on real-world benchmark data. The scores are then compared after applying use-case weighting factors:
Gaming 1080p: CPU 55% · GPU 45% — CPU matters more at low res
Gaming 1440p: CPU 40% · GPU 60% — more GPU-dependent
Gaming 4K: CPU 25% · GPU 75% — heavily GPU-limited
Streaming: CPU 65% · GPU 35% — encoding taxes the CPU
3D Render: CPU 70% · GPU 30% — CPU-dominant workload
Bottleneck % = |CPU weighted score − GPU weighted score| / max(scores) × 100
What Is a Good Bottleneck Percentage?
Does RAM Affect Bottlenecking?
Yes. Insufficient RAM can create its own bottleneck. If your system runs out of physical RAM, it starts using slower virtual memory (your storage drive), which causes severe performance drops, stuttering, and long loading times. For gaming, 16 GB is the current minimum recommended amount, with 32 GB being the new standard for future-proofing. For 3D rendering and video editing, 32–64 GB is advisable.
Dual-channel RAM (two sticks instead of one) also makes a meaningful difference for AMD Ryzen processors, which rely on fast memory bandwidth for optimal performance. Running a single 16 GB stick instead of two 8 GB sticks can noticeably reduce Ryzen CPU performance.
Tips for Reducing Bottlenecks
Frequently Asked Questions
Is a GPU bottleneck always bad?
No — a GPU bottleneck in gaming is generally considered healthy. It means your CPU is powerful enough to keep the GPU fully loaded. Your target should be near-100% GPU utilisation with CPU utilisation below that threshold. A CPU bottleneck is more problematic because it means you are not getting full value from your GPU investment.
Why does the bottleneck change with resolution?
At 1080p, frames are rendered relatively quickly, so the CPU (which handles game logic, AI, physics, and draw calls) becomes the bottleneck more easily. At 4K, each frame requires four times the pixels of 1080p, shifting almost all the burden to the GPU. The same CPU-GPU pair can go from CPU-bottlenecked at 1080p to GPU-bottlenecked at 4K.
Should I always aim for 0% bottleneck?
Not necessarily. A perfect 0% balance is rare and not required. Anything under 10% is excellent, and under 20% is perfectly acceptable for most users. Chasing a zero bottleneck can lead to unnecessary spending on components that offer diminishing returns.
Does the calculator account for overclocking?
The performance scores used in this calculator are based on stock (default) clock speeds. If you have overclocked your CPU or GPU, your real-world performance gap will be slightly smaller than shown.