SF3 Decreased FPS when looking in a certain direction.

[11343]

Usually my fps (with vsync on) is at around 60 fps but occasionally when i look in a certain direction it will drop to 30 fps, if i look away it goes up to 60 again, but if i look back again it drops...
This happens pretty often and i think most of the time it happens my automatic sieve farm is in the screen (sometimes behind wood slabs though).
Can somebody help me or tell me why this keeps happening?
Also i am using rivens "full" algorithm if that helps.

 

[11343]

i managed to document this with the lagmeter,

note that all i was doing here is looking to the right, then back at the sieves

 

[JoeBidenVaping]

I've actually had this same issue as well

On the optifine lagometer, the left higher points of the graph represent when i look at the FPS halving direction. The other half represents when I look away.