Bottleneck calculator

How the calculator works

For every frame of a game, the processor works out what happens and what to draw, and the graphics card draws it. The two work at the same time on different frames, so whichever is slower sets the frame rate. The calculator gives each part a figure for games and compares the two at each resolution.

• The processor’s figure is mostly its single-core speed, with a small share of multi-core speed counted up to what a current eight-core chip offers: games lean on a few fast threads and rarely use more than eight cores. Two families are adjusted by what published game tests show. AMD’s X3D chips count a quarter faster, for the extra cache no single-core test sees, and Intel’s Core Ultra 200S chips 7% slower, for their memory latency.
• The graphics card’s figure is its gaming performance. A higher resolution makes every frame more work for the graphics card — at 1440p it draws about 70% as many frames as at 1080p, and at 4K about 42% — while the processor’s share of each frame hardly changes. That is why the same pair can be held back by the processor at 1080p and by the graphics card at 4K.

Both figures come from the reference dataset the Bottleneck app uses to judge the hardware it measures. The result is for a typical game at high settings. Strategy, simulation and large multiplayer games lean on the processor much more than that; visually demanding single-player games lean on the graphics card. Lower settings, and upscaling such as DLSS, FSR and XeSS, move the balance towards the processor, as a lower resolution would.

Why there is no bottleneck percentage to the decimal point

Part names cannot support that precision. The same pair behaves differently from one game to the next and with every change of settings, so the calculator gives the direction and a rounded size, and shows how it got there.

Common pairings

Which part is likely to set the pace in a typical game at high settings. Choose a pairing to see the detail.

What part names cannot tell you

Two PCs with the same processor and graphics card can perform very differently. The usual reasons cost nothing to fix, and each makes the hardware look slower than it is:

• Memory running below its rated speed, because XMP or EXPO was never switched on.
• Memory in single channel, from one stick or two in the wrong slots.
• A monitor stuck at 60 Hz, or plugged into the motherboard instead of the graphics card.
• Heat, when the processor or the graphics card slows itself down to stay within its limit.
• Hardware-accelerated GPU scheduling switched off, which on recent NVIDIA cards also rules out frame generation.
• A power plan, battery mode or background program holding the processor back.

If your graphics card sits well below full use while a game runs slower than you want, low GPU usage in games goes through the causes in order.

Questions

What is a bottleneck in a PC?

The part that sets the pace. In a game it is whichever of the processor and the graphics card takes longer over its share of each frame; the other part then waits. Every PC has one in every game, so the useful questions are which part it is and whether it is the one you would choose.

Is it bad for the graphics card to be the bottleneck?

No — in games it is usually what you want. The graphics card is normally the most expensive part, and when it sets the pace it is working flat out. A processor that holds the graphics card back is the case worth fixing, because part of what you paid for the card goes unused.

Does resolution change the bottleneck?

Yes, more than anything else. Raising the resolution gives the graphics card more work per frame and leaves the processor’s work much the same, so the balance moves towards the graphics card. A pair held back by the processor at 1080p is often held back by the graphics card at 4K.

Why is my processor or graphics card not in the list?

The list covers the desktop processors and graphics cards most people own, from the dataset the Bottleneck app uses. Laptop chips are left out, because the same chip runs at very different power in different laptops, and so is graphics built into the processor, which shares its power and memory and sets the pace in almost every game. The Bottleneck app measures whatever parts your PC has, listed or not.

How can I tell whether my own PC is held back?

Watch the graphics card’s usage while you play, or lower the resolution and see whether the frame rate rises. CPU or GPU bottleneck explains both. Bottleneck’s game measurement goes further: it records, frame by frame, whether the processor or the graphics card held the game back.

Should I upgrade my processor or my graphics card?

Fix the free things first, then upgrade the part that holds back the games you play, at the resolution you play them. If the processor holds the card back only at 1080p and you play at 1440p, a processor upgrade would change little. The Bottleneck app suggests an upgrade only once the free fixes are done, and says what it would buy you.