-unroll 10 -ffa_block 6144 -ffa_block_fetch 1536 should work fine.

Sbs switch not needed atm.

That will be the GPU usage Bug a fair amount of us are suffering from, suspending GPU usage, waiting for the app to exit (watch task manager), then resuming often gets high GPU usage again,

Claggy

Yes, if GPU processing few heavely blanked tasks there can be GPU usage drop even with few tasks per card.
But I think there is the way to distinguish such pattern from GPU low usage bug pattern.

Heavely blanked pattern should have almost 100% spikes when FFA done on GPU (it's best optimized partion IMHO cause I worked on it from Brook+ times). Blanking affects on processing between FFAs and FFA itself should make use of almost all GPU.
Whereas low usage bug pattern will shouw steady low % perhaps.

Not sure in that but you can make observations and improve my suggestion.

WoW, good observation!
No, I think not.

There is key difference in buffer allocations for MB and AP.
While MB does more or less homogenic calculations AP implements 2 almost independent sections - main loop and FFA.
For FFA we need different buffers (different number, different sizes) than for main loop single pulse search.
Hence there is only once buffers allocation in MB, at the beginning, but constant buffers recreation/discarding for AP.
Before there was opinion that low GPU usage bug can be connected with orphaned OpenCL resources left behind when task finished. Indeed, I did not directly deallocate buffers in MB leaving cleanup for OS/OpenCL runtime (as should be when OS process get killed).
But I do buffers deallocation in AstroPulse ! When transition from main loop to FFA occurs some of main loop buffers are deallocated and FFA ones are allocated, and vice versa. So, the problem not in deallocation, the problem in allocation!

No clue how to fix it on our end still, but at least it's good bug report to AMD.

That is exactly what it looks like on mine as well.

I must note that I hadn't noticed the error before optimizing the settings.

I'm thinking about going back to see if it disappears with the standard settings...

I only ever run 1 task per GPU, it enables me to see what the app is doing, rather than having multiple apps masking the problem,

Claggy

BTW, look for memory graph.
There are "spikes"  - they corresponds short FFA (most of them).
Look how often they occur on "fast"task and how wider (X-axis is time so wider =slower) they are on "slow" task.
But amount of computation between them is just the same!
Hence we have slowdown not just in some area of algorithm. Whole processing more or less equally slowed. single pulse search takes more and FFa takes more too.
It's important result cause it can decline assumption that there are just many false positives from near to threshold reesults in FFA so much more bus transfers are needed. In that case FFA would took much longer while single pulse (main loop) - not. So we would see disproportional increase in max or min memory usage time.