diff --git a/lib/CGameState.cpp b/lib/CGameState.cpp
index ba383f680..2b524363d 100644
--- a/lib/CGameState.cpp
+++ b/lib/CGameState.cpp
@@ -724,20 +724,13 @@ ui32 CStack::Speed( int turn /*= 0*/ ) const
 	int percentBonus = 0;
 	for(int g=0; g<features.size(); ++g)
 	{
-		if(features[g].type == StackFeature::SPEED_BONUS, -1024, turn)
+		if(features[g].type == StackFeature::SPEED_BONUS)
 		{
 			percentBonus += features[g].additionalInfo;
 		}
 	}
 
-	if(percentBonus < 0)
-	{
-		speed = (abs(percentBonus) * speed)/100;
-	}
-	else
-	{
-		speed = ((100 + percentBonus) * speed)/100;
-	}
+	speed = ((100 + percentBonus) * speed)/100;
 
 	//bind effect check
 	if(getEffect(72)) 
diff --git a/lib/NetPacksLib.cpp b/lib/NetPacksLib.cpp
index 26650d48f..daf36e527 100644
--- a/lib/NetPacksLib.cpp
+++ b/lib/NetPacksLib.cpp
@@ -910,7 +910,7 @@ static std::vector<StackFeature> stackEffectToFeature(const CStack::StackEffect
 		sf.push_back(featureGenerator(StackFeature::SPEED_BONUS, 0, VLC->spellh->spells[sse.id].powers[sse.level], sse.turnsRemain));
 		break;
 	case 54: //slow
-		sf.push_back(featureGenerator(StackFeature::SPEED_BONUS, 0, 0, sse.turnsRemain, -1 * VLC->spellh->spells[sse.id].powers[sse.level]));
+		sf.push_back(featureGenerator(StackFeature::SPEED_BONUS, 0, 0, sse.turnsRemain, -1 * ( 100 - VLC->spellh->spells[sse.id].powers[sse.level] ) ));
 		break;
 	case 55: //slayer
 		sf.push_back(featureGenerator(StackFeature::SLAYER, 0, sse.level, sse.turnsRemain));