diff --git a/src/game/Creature.cpp b/src/game/Creature.cpp
index faa91bf13..fbfdc8189 100644
--- a/src/game/Creature.cpp
+++ b/src/game/Creature.cpp
@@ -444,7 +444,7 @@ void Creature::Update(uint32 diff)
 
             RegenerateMana();
 
-            m_regenTimer = 2000;
+            m_regenTimer = REGEN_TIME_FULL;
             break;
         }
         case DEAD_FALLING:
diff --git a/src/game/Player.cpp b/src/game/Player.cpp
index 0006f266b..66f49eea8 100644
--- a/src/game/Player.cpp
+++ b/src/game/Player.cpp
@@ -1242,7 +1242,12 @@ void Player::Update( uint32 p_time )
 
     if (isAlive())
     {
-        RegenerateAll();
+        // if no longer casting, set regen power as soon as it is up.
+        if (!IsUnderLastManaUseEffect())
+            SetFlag(UNIT_FIELD_FLAGS_2, UNIT_FLAG2_REGENERATE_POWER);
+
+        if (!m_regenTimer)
+            RegenerateAll();
     }
 
     if (m_deathState == JUST_DIED)
@@ -1903,36 +1908,33 @@ void Player::RewardRage( uint32 damage, uint32 weaponSpeedHitFactor, bool attack
     ModifyPower(POWER_RAGE, uint32(addRage*10));
 }
 
-void Player::RegenerateAll()
+void Player::RegenerateAll(uint32 diff)
 {
-    if (m_regenTimer != 0)
-        return;
-    uint32 regenDelay = 2000;
-
     // Not in combat or they have regeneration
-    if( !isInCombat() || HasAuraType(SPELL_AURA_MOD_REGEN_DURING_COMBAT) ||
+    if (!isInCombat() || HasAuraType(SPELL_AURA_MOD_REGEN_DURING_COMBAT) ||
         HasAuraType(SPELL_AURA_MOD_HEALTH_REGEN_IN_COMBAT) || IsPolymorphed() )
     {
-        RegenerateHealth();
+        RegenerateHealth(diff);
         if (!isInCombat() && !HasAuraType(SPELL_AURA_INTERRUPT_REGEN))
         {
-            Regenerate(POWER_RAGE);
+            Regenerate(POWER_RAGE, diff);
             if(getClass() == CLASS_DEATH_KNIGHT)
-                Regenerate(POWER_RUNIC_POWER);
+                Regenerate(POWER_RUNIC_POWER, diff);
         }
     }
 
-    Regenerate( POWER_ENERGY );
+    Regenerate(POWER_ENERGY, diff);
 
-    Regenerate( POWER_MANA );
+    Regenerate(POWER_MANA, diff);
 
-    if(getClass() == CLASS_DEATH_KNIGHT)
-        Regenerate( POWER_RUNE );
+    if (getClass() == CLASS_DEATH_KNIGHT)
+        Regenerate(POWER_RUNE, diff);
 
-    m_regenTimer = regenDelay;
+    m_regenTimer = REGEN_TIME_FULL;
 }
 
-void Player::Regenerate(Powers power)
+// diff contains the time in milliseconds since last regen.
+void Player::Regenerate(Powers power, uint32 diff)
 {
     uint32 curValue = GetPower(power);
     uint32 maxValue = GetMaxPower(power);
@@ -1971,8 +1973,10 @@ void Player::Regenerate(Powers power)
         case POWER_RUNE:
         {
             for(uint32 i = 0; i < MAX_RUNES; ++i)
-                if(uint8 cd = GetRuneCooldown(i))           // if we have cooldown, reduce it...
-                    SetRuneCooldown(i, cd - 1);             // ... by 2 sec (because update is every 2 sec)
+            {
+                if(uint16 cd = GetRuneCooldown(i))           // if we have cooldown, reduce it...
+                    SetRuneCooldown(i, (cd < diff) ? 0 : cd - diff);
+            }
         }   break;
         case POWER_FOCUS:
         case POWER_HAPPINESS:
@@ -1990,6 +1994,9 @@ void Player::Regenerate(Powers power)
                 addvalue *= ((*i)->GetModifier()->m_amount + 100) / 100.0f;
     }
 
+    // addvalue computed on a 2sec basis. => update to diff time
+    addvalue *= float(diff) / REGEN_TIME_FULL;
+
     if (power != POWER_RAGE && power != POWER_RUNIC_POWER)
     {
         curValue += uint32(addvalue);
@@ -2006,7 +2013,7 @@ void Player::Regenerate(Powers power)
     SetPower(power, curValue);
 }
 
-void Player::RegenerateHealth()
+void Player::RegenerateHealth(uint32 diff)
 {
     uint32 curValue = GetHealth();
     uint32 maxValue = GetMaxHealth();
@@ -2043,6 +2050,8 @@ void Player::RegenerateHealth()
     if(addvalue < 0)
         addvalue = 0;
 
+    addvalue *= (float)diff / REGEN_TIME_FULL;
+
     ModifyHealth(int32(addvalue));
 }
 
@@ -19614,7 +19623,7 @@ void Player::ResyncRunes(uint8 count)
     for(uint32 i = 0; i < count; ++i)
     {
         data << uint8(GetCurrentRune(i));                   // rune type
-        data << uint8(255 - (GetRuneCooldown(i) * 51));     // passed cooldown time (0-255)
+        data << uint8(255 - ((GetRuneCooldown(i) / REGEN_TIME_FULL) * 51));     // passed cooldown time (0-255)
     }
     GetSession()->SendPacket(&data);
 }
diff --git a/src/game/Player.h b/src/game/Player.h
index fee045180..f9a16aaec 100644
--- a/src/game/Player.h
+++ b/src/game/Player.h
@@ -269,7 +269,7 @@ struct Areas
 };
 
 #define MAX_RUNES       6
-#define RUNE_COOLDOWN   5                                   // 5*2=10 sec
+#define RUNE_COOLDOWN   10000                               // msec
 
 enum RuneType
 {
@@ -282,9 +282,9 @@ enum RuneType
 
 struct RuneInfo
 {
-    uint8 BaseRune;
-    uint8 CurrentRune;
-    uint8 Cooldown;
+    uint8  BaseRune;
+    uint8  CurrentRune;
+    uint16 Cooldown;                                        // msec
 };
 
 struct Runes
@@ -1403,9 +1403,9 @@ class MANGOS_DLL_SPEC Player : public Unit
         void RewardRage( uint32 damage, uint32 weaponSpeedHitFactor, bool attacker );
         void SendPetSkillWipeConfirm();
         void CalcRage( uint32 damage,bool attacker );
-        void RegenerateAll();
-        void Regenerate(Powers power);
-        void RegenerateHealth();
+        void RegenerateAll(uint32 diff = REGEN_TIME_FULL);
+        void Regenerate(Powers power, uint32 diff);
+        void RegenerateHealth(uint32 diff);
         void setRegenTimer(uint32 time) {m_regenTimer = time;}
         void setWeaponChangeTimer(uint32 time) {m_weaponChangeTimer = time;}
 
@@ -2208,10 +2208,10 @@ class MANGOS_DLL_SPEC Player : public Unit
         uint8 GetRunesState() const { return m_runes->runeState; }
         uint8 GetBaseRune(uint8 index) const { return m_runes->runes[index].BaseRune; }
         uint8 GetCurrentRune(uint8 index) const { return m_runes->runes[index].CurrentRune; }
-        uint8 GetRuneCooldown(uint8 index) const { return m_runes->runes[index].Cooldown; }
+        uint16 GetRuneCooldown(uint8 index) const { return m_runes->runes[index].Cooldown; }
         void SetBaseRune(uint8 index, uint8 baseRune) { m_runes->runes[index].BaseRune = baseRune; }
         void SetCurrentRune(uint8 index, uint8 currentRune) { m_runes->runes[index].CurrentRune = currentRune; }
-        void SetRuneCooldown(uint8 index, uint8 cooldown) { m_runes->runes[index].Cooldown = cooldown; m_runes->SetRuneState(index, (cooldown == 0) ? true : false); }
+        void SetRuneCooldown(uint8 index, uint16 cooldown) { m_runes->runes[index].Cooldown = cooldown; m_runes->SetRuneState(index, (cooldown == 0) ? true : false); }
         void ConvertRune(uint8 index, uint8 newType);
         void ResyncRunes(uint8 count);
         void AddRunePower(uint8 index);
diff --git a/src/game/Spell.cpp b/src/game/Spell.cpp
index 2c3b22ef0..f917dfd6e 100644
--- a/src/game/Spell.cpp
+++ b/src/game/Spell.cpp
@@ -5039,6 +5039,15 @@ SpellCastResult Spell::CheckPower()
     if(m_CastItem)
         return SPELL_CAST_OK;
 
+    // Do precise power regen on spell cast
+    if (m_powerCost > 0 && m_caster->GetTypeId() == TYPEID_PLAYER)
+    {
+        Player* playerCaster = (Player*)m_caster;
+        uint32 diff = REGEN_TIME_FULL - m_caster->GetRegenTimer();
+        if (diff >= REGEN_TIME_PRECISE)
+            playerCaster->RegenerateAll(diff);
+    }
+
     // health as power used - need check health amount
     if(m_spellInfo->powerType == POWER_HEALTH)
     {
diff --git a/src/game/Unit.h b/src/game/Unit.h
index 9726aa874..41c037990 100644
--- a/src/game/Unit.h
+++ b/src/game/Unit.h
@@ -856,6 +856,10 @@ typedef std::set<uint64> GuardianPetList;
 #define ATTACK_DISPLAY_DELAY 200
 #define MAX_PLAYER_STEALTH_DETECT_RANGE 45.0f               // max distance for detection targets by player
 
+// Regeneration defines
+#define REGEN_TIME_FULL     2000                            // For this time difference is computed regen value
+#define REGEN_TIME_PRECISE  500                             // Used in Spell::CheckPower for precise regeneration in spell cast time
+
 struct SpellProcEventEntry;                                 // used only privately
 
 class MANGOS_DLL_SPEC Unit : public WorldObject
@@ -1423,9 +1427,18 @@ class MANGOS_DLL_SPEC Unit : public WorldObject
         uint32 SpellCriticalDamageBonus(SpellEntry const *spellProto, uint32 damage, Unit *pVictim);
         uint32 SpellCriticalHealingBonus(SpellEntry const *spellProto, uint32 damage, Unit *pVictim);
 
-        void SetLastManaUse(uint32 spellCastTime) { m_lastManaUse = spellCastTime; }
+        void SetLastManaUse(uint32 spellCastTime)
+        {
+            if (GetTypeId() == TYPEID_PLAYER && !IsUnderLastManaUseEffect())
+            {
+                RemoveFlag(UNIT_FIELD_FLAGS_2, UNIT_FLAG2_REGENERATE_POWER);
+            }
+            m_lastManaUse = spellCastTime;
+        }
         bool IsUnderLastManaUseEffect() const;
 
+        uint32 GetRegenTimer() const { return m_regenTimer; }
+
         void SetContestedPvP(Player *attackedPlayer = NULL);
 
         void MeleeDamageBonus(Unit *pVictim, uint32 *damage, WeaponAttackType attType, SpellEntry const *spellProto = NULL);
diff --git a/src/shared/revision_nr.h b/src/shared/revision_nr.h
index 654a1f652..e3c6ae35b 100644
--- a/src/shared/revision_nr.h
+++ b/src/shared/revision_nr.h
@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "8476"
+ #define REVISION_NR "8477"
 #endif // __REVISION_NR_H__