function calculateBottleneck() {
var cpu = parseFloat(document.getElementById('cpuScore').value);
var gpu = parseFloat(document.getElementById('gpuScore').value);
var res = parseFloat(document.getElementById('resolution').value);
var resultsDiv = document.getElementById('resultsArea');
var percentDiv = document.getElementById('bottleneckPercent');
var typeDiv = document.getElementById('bottleneckType');
var adviceDiv = document.getElementById('bottleneckAdvice');
if (isNaN(cpu) || isNaN(gpu) || cpu <= 0 || gpu (cpu * 0.15)) {
// CPU is much weaker than GPU
resultsDiv.style.backgroundColor = "#fff4f4";
percentDiv.style.color = "#d93025";
type = "Processor (CPU) Bottleneck Detected";
percentDiv.innerHTML = bottleneckPercentage + "%";
advice = "Your CPU is significantly slower than your GPU for this resolution. This means your graphics card is 'waiting' for the processor to finish its tasks. To fix this, consider upgrading your CPU or increasing your resolution to 1440p/4K to put more load on the GPU.";
} else if (difference < -(cpu * 0.15)) {
// GPU is much weaker than CPU
resultsDiv.style.backgroundColor = "#fff9e6";
percentDiv.style.color = "#f9ab00";
type = "Graphics Card (GPU) Bottleneck Detected";
percentDiv.innerHTML = bottleneckPercentage + "%";
advice = "Your GPU is the limiting factor in this build. Your CPU is capable of delivering more frames, but the graphics card has reached its limit. This is generally preferred in gaming setups. To improve FPS, you would need a more powerful graphics card.";
} else {
// Well balanced
resultsDiv.style.backgroundColor = "#e6f4ea";
percentDiv.style.color = "#1e8e3e";
type = "Excellent Hardware Match";
percentDiv.innerHTML = bottleneckPercentage + "%";
advice = "Your CPU and GPU are well-balanced for this resolution. There is less than a 15% performance gap, meaning both components will be utilized efficiently in most modern games.";
}
typeDiv.innerHTML = type;
adviceDiv.innerHTML = "Analysis: " + advice;
}
Understanding CPU and GPU Bottlenecks
A bottleneck in a PC occurs when one component limits the potential of another. In gaming, this usually refers to the relationship between your Central Processing Unit (CPU) and your Graphics Processing Unit (GPU). When your hardware is mismatched, you are paying for performance that you cannot actually use.
What is a CPU Bottleneck?
A CPU bottleneck happens when the processor is not fast enough to process the game logic and draw calls required by the graphics card. This often results in stuttering, lower minimum frame rates, and your GPU usage staying well below 90-100%.
Common at: 1080p resolution or lower.
Symptoms: Low GPU usage, frame drops in crowded game areas, and high CPU usage across all cores.
Fix: Upgrade the CPU, increase resolution, or close background applications.
What is a GPU Bottleneck?
A GPU bottleneck occurs when the graphics card is working at its maximum capacity (99-100% usage) while the CPU is still capable of handling more data. In the gaming world, this is actually the ideal scenario. It ensures you are getting the full value out of your expensive graphics card and results in a smoother visual experience.
Common at: 1440p and 4K resolutions.
Symptoms: 99% GPU usage, consistent frame delivery, and fluid gameplay.
Fix: Lower graphical settings, use DLSS/FSR, or upgrade the graphics card.
Why Resolution Matters
Resolution is the most significant factor in shifting the bottleneck. At 1080p, the CPU has a massive responsibility to feed the GPU data quickly. As you move to 4K, the GPU has to work significantly harder to render four times the pixels, which slows the GPU down enough that the CPU can easily keep up. This is why a "weak" CPU might bottleneck a system at 1080p but perform perfectly at 4K.
Realistic Example:
If you pair an Intel Core i3-12100 with an NVIDIA RTX 4090 at 1080p, you will experience a massive CPU bottleneck. The 4090 is so fast that the i3 cannot send instructions quickly enough. However, if you play at 4K Ultra settings, the 4090 slows down due to the heavy rendering load, and the i3 will likely keep up much better, reducing the bottleneck percentage significantly.