What determines a game's CPU/GPU intensity lies in how much processing power it demands from both components.
What determines a game's CPU/GPU intensity lies in how much processing power it demands from both components.
I was curious about what factors decide whether a game is GPU or CPU heavy. Is this really something important or is it just another point people say without much truth behind it? When a game doesn’t look very visually demanding, does the CPU become the issue if you notice low frames? Could it be related to how the engine is built, with some games distributing tasks differently? Or is it about the type of game—like complex AI usually means more CPU usage?
In general, a GPU excels at handling straightforward calculations involving large volumes of data at once. This stems from its design, which features a straightforward control or logic component. Refer to the diagram provided by Nvidia for a clear comparison between CPUs and GPUs.
Most of the CPU architecture is dedicated to complex control tasks, cache management, and other functions, leaving less space for ALUs (arithmetic logic units). Consequently, GPUs become extremely efficient when processing simple parallel operations, such as numerous linear algebra calculations. However, they struggle significantly with intricate instructions, particularly conditional statements like if-then-else constructs, where CPUs perform much better.
GPUs require their instructions to closely align with "SIMD" — Single Instruction Multiple Data — meaning they execute the same operation across many data points simultaneously. If they encounter varied instructions (such as those executed by operating system processes), performance drops sharply.
These specialized GPUs are highly effective for specific problem types. CPUs, on the other hand, offer greater versatility.
GPUs particularly shine in two areas:
- Floating-point calculations (used in physics and graphics)
- Performing identical operations across vast datasets at once, a form of "parallelism"
Additionally, general computing tasks are relatively rare where GPUs outperform CPUs. Even without the branching/switching constraints they face, GPUs would still consist largely of numerous slower cores.
It about what devs focus their optimization on. It is a thing, but you might not notice it with balanced system. However if you have lacked with CPU (mainly) and go to play CPU intensive/optimized game, you will note things aren't as smooth as they would. Fps might not be different, but other things will feel different.
Usually most games are GPU optimized/intensive. CSGO, Minecraft and Battlefield games after BF4 have been most known CPU optimized games.
Games relying heavily on logic calculations for determining states require greater CPU power. On the other hand, games with extensive rendering tasks and intricately designed shapes tend to demand more from the GPU. When a game is primarily GPU-focused and not CPU-heavy, it usually indicates that many elements are predefined and don’t need real-time computation. Civilization serves as a prime example of a CPU-intensive title, due to its complex interdependencies requiring constant CPU management.