break everything again, scheck and other loop sleeps now sleep for a proper 10th of a second instead of just 1 tick at whatever FPS. Throw some scheck like calls in the zas ticker.

code/controllers/ProcessScheduler/core/process.dm

@@ -196,7 +196,7 @@ datum/controller/process/proc/scheck(var/tickId = 0)
 	// For each tick the process defers, it increments the cpu_defer_count so we don't
 	// defer indefinitely
 	if (world.cpu >= cpu_threshold + cpu_defer_count * 10)
-		sleep(1)
+		sleep(calculateticks(1))
 		cpu_defer_count++
 		last_slept = world.timeofday
 	else
@@ -206,7 +206,7 @@ datum/controller/process/proc/scheck(var/tickId = 0)
 
 		if (world.timeofday > last_slept + sleep_interval)
 			// If we haven't slept in sleep_interval ticks, sleep to allow other work to proceed.
-			sleep(0)
+			sleep(calculateticks(1))
 			last_slept = world.timeofday
 
 datum/controller/process/proc/update()

code/controllers/ProcessScheduler/core/updateQueueWorker.dm

@@ -46,7 +46,7 @@ datum/updateQueueWorker/proc/doWork()
 		// in the next tick.
 		uq_dbg("tick went into overtime with world.cpu = [world.cpu], deferred next update to next tick [1+(world.time / world.tick_lag)]")
 
-		spawn(1)
+		spawn(calculateticks(1))
 			doWork()
 	else
 		spawn(0) // Execute anonymous function immediately as if we were in a while loop...

code/controllers/Processes/air.dm

@@ -22,3 +22,4 @@
 
 				air_processing_killed = TRUE
 				air_master.failed_ticks = 0
+		scheck()

code/controllers/Processes/ticker.dm

@@ -20,6 +20,7 @@ var/global/datum/controller/process/ticker/tickerProcess
 			ticker.pregame()
 
 /datum/controller/process/ticker/doWork()
+	scheck()
 	var/currentTime = world.timeofday
 
 	if(currentTime < lastTickerTime) // check for midnight rollover

code/controllers/garbage.dm

@@ -63,6 +63,11 @@ var/soft_dels = 0
 
 			hard_dels++
 			remainingForceDelPerTick--
+			if(world.cpu > 80)
+				#ifdef GG_DEBUG
+				WARNING("GC process sleeping due to high CPU usage!")
+				#endif
+				sleep(calculateticks(2))
 
 #ifdef GC_DEBUG
 #undef GC_DEBUG