I was wondering playing at 1080p on newer GPU's is actually making the CPU work harder ?

There are less pixels to process at 1080p so it stands to reason that CPUs don't have to work as hard as at 1440P or 4k which have more pixels to process.

The above answer is false, you’re correct, the lower the resolution more load is shifted to the CPU causing your FPS to be dependent on your CPU horsepower rather than your GPU (called a bottleneck) Upping your resolution will take advantage of the new high end powerful GPUs, reducing ur CPU load and actually make games run smoother.

Edited August 2, 20214 yr by johnnycaptain

On 8/2/2021 at 3:41 PM, johnnycaptain said:

The above answer is false, you’re correct, the lower the resolution more load is shifted to the CPU causing your FPS to be dependent on your CPU horsepower rather than your GPU (called a bottleneck) Upping your resolution will take advantage of the new high end powerful GPUs, reducing ur CPU load and actually make games run smoother.

Different kinds of work are done by the CPU and GPU, and reducing the workload on one does not "shift" workload to the other.

Reducing the frame complexity (and thus GPU load) can impose a higher workload on the CPU in some circumstances, not by shifting work, but rather it may eliminate an existing bottleneck in the GPU's frame processing, allowing it to accept frames at a higher rate and potentially driving the CPU to work harder to produce frames at the higher rate. 

However, whether that happens will depend a great deal on how things are configured.  For example, in P3D with frame rate set at unlimited, the CPU is generally always running all-out anyway, first and foremost trying to saturate the GPU, and producing lookahead frames when the GPU is saturated (e.g. can't accept frames any faster).  If you limit the frame rate by locking the GPU to a 30Hz hardware refresh rate, then the CPU will only attempt to produce enough frames to keep up with that 30 Hz refresh rate, and assuming it is keeping up at 30 fps, reducing the GPU workload will only cause the GPU load to drop without changing the CPU load--it's still humming along at 30 fps.  Conversely, if the GPU is locked to the hardware refresh rate, adding workload to the GPU (e.g. higher res, more AA etc) will result in the GPU load going up without a change in CPU load until the GPU reaches saturation, and then at that point the CPU load will drop off as the GPU limits frame production at its lower rate.

So...the answer is, as often is the case: "it depends."  Which sim, how it's configured, and graphics device(s) (resolution, AA, fixed or variable refresh rate etc) all enter into the equation.