Increase SR for beatmaps with high bpm streams (220bpm+)

osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs

@@ -21,6 +21,10 @@ protected override double StrainValueOf(OsuDifficultyHitObject current)
         {
             double distance = current.TravelDistance + current.JumpDistance;
 
+            double speedBonus = 1.0;
+            if (current.StrainTime < 68) // 68 = 220 BPM 1/4th snapping in MS.
+                speedBonus = 68 / current.StrainTime; // 1.09x for 240 BPM, 1.18x for 260 BPM, 1.36x for 300 BPM, etc.
+
             double speedValue;
             if (distance > single_spacing_threshold)
                 speedValue = 2.5;
@@ -33,7 +37,7 @@ protected override double StrainValueOf(OsuDifficultyHitObject current)
             else
                 speedValue = 0.95;
 
-            return speedValue / current.StrainTime;
+            return speedValue * speedBonus / current.StrainTime;
         }
     }
 }