This free bottleneck calculator doesn’t give you a made-up percentage. It shows which part — CPU or GPU — actually limits your frame rate in each of 12 popular games at your resolution, then simulates upgrading each part so you can see which upgrade genuinely gains you more FPS before spending a penny.
Why we don’t give you a “bottleneck percentage”
Most bottleneck calculators output a single number — “your CPU bottlenecks your GPU by 13%” — and that number is fiction. There is no such measurement. The limiting component changes per game and per resolution: CS2 at 1080p is CPU-limited on almost any hardware you can buy, while Cyberpunk 2077 at 4K is GPU-limited on everything. Averaging those into one percentage tells you nothing you can act on.
Every system is bottlenecked by something in every game — that’s physics, not a fault. The only question that matters is the one this tool answers: if you spent money on an upgrade today, which part would actually buy you frames in the games you play? Our engine is calibrated against published July 2026 benchmarks — the same model behind our FPS calculator — so the answer is grounded in real measured performance, not a made-up formula.
Bottleneck calculator — common questions
How does this bottleneck calculator work?
For each game it computes two ceilings from benchmark-calibrated data: the FPS your GPU could render at your resolution and settings, and the FPS your CPU could feed it. Your real frame rate is the lower ceiling — whichever part sets it is your bottleneck in that game. It then simulates a one-tier upgrade of each part to show which would gain more.
Why doesn’t it show a single percentage?
Because a single percentage is fiction — the bottleneck changes per game and per resolution. We show the per-game truth and the average FPS gain from each possible upgrade instead, which is the number you can actually act on.
Is some bottleneck always present?
Yes — every system is limited by something in every game, and that’s normal. The goal isn’t zero bottleneck (impossible); it’s avoiding a badly mismatched pairing where one expensive part sits mostly idle. If both simulated upgrades show similar modest gains, your build is well balanced.
Should I upgrade my CPU or GPU first?
Whichever the simulation shows gaining more in the games and resolution you actually play. Rule of thumb: 1440p/4K pushes load onto the GPU; high-refresh 1080p esports leans on the CPU. Still unsure? Ask us — upgrade advice and fitting is what we do in Harrow.
Ready to fix the bottleneck?
We supply and fit CPU and GPU upgrades in Harrow — and we’ll buy your old part off you too. Send us your result on WhatsApp and we’ll quote the upgrade, fitted, same week.