in forza horizon 4, what does this mean?
benchmark mode results
Where do you see that? In the settings?
what do you mean?
Means your GPU can be utilized 99% with your current CPU & GPU setup. Which also means no bottleneck. There's no issues here.
Well this technically means the GPU is a bottleneck for his PC since he runs it at 100% unless the rest of the build is also running at 100%. He could get more frames/better resolution/better settings with a more powerful one but if he is fine the results he gets its definitely not a cause for concern.
more powerful CPU or GPU? CPU i presume?
GPU. If it is running at 100%, it means the rest of your parts could handle more. When your GPU is running at 50% but your CPU at 100%, then you would need a stronger CPU if you wanted to make use of all the rest of the performance the GPU could give you.
What matters in the end if whether or not you are happy with the performance you are getting.
If the resolution/settings/framerate is fine for you, it should not be any concern but if you are playing on high and would like ultra or a higher and more concistent framerate for example, going for a stronger GPU would be possible provided that your CPU isnt alos always running at 100%.
both are running at 100%
Then that means your PC is running to the maximum potential it can. This also means if you wanted to upgrade the GPU, you would need a stronger CPU to get more performance from it, at least in this title.
Not all titles are properly coded/optimized so the result you have in Forza 4 might not be the same in all games.