diff --git a/Sources/BaseDataTransaction.swift b/Sources/BaseDataTransaction.swift
index 59fe52f..cae9c84 100644
--- a/Sources/BaseDataTransaction.swift
+++ b/Sources/BaseDataTransaction.swift
@@ -429,7 +429,7 @@ public /*abstract*/ class BaseDataTransaction {
     
     internal let context: NSManagedObjectContext
     internal let transactionQueue: DispatchQueue
-    internal let childTransactionQueue = DispatchQueue.serial("com.corestore.datastack.childTransactionQueue")
+    internal let childTransactionQueue = DispatchQueue.serial("com.corestore.datastack.childTransactionQueue", qos: .utility)
     internal let supportsUndo: Bool
     internal let bypassesQueueing: Bool
     internal var isCommitted = false
diff --git a/Sources/CoreStoreDefaults.swift b/Sources/CoreStoreDefaults.swift
index 966d4f5..26ddec6 100644
--- a/Sources/CoreStoreDefaults.swift
+++ b/Sources/CoreStoreDefaults.swift
@@ -69,7 +69,7 @@ public enum CoreStoreDefaults {
 
     // MARK: Private
 
-    private static let defaultStackBarrierQueue = DispatchQueue.concurrent("com.coreStore.defaultStackBarrierQueue")
+    private static let defaultStackBarrierQueue = DispatchQueue.concurrent("com.coreStore.defaultStackBarrierQueue", qos: .userInteractive)
 
     private static var defaultStackInstance: DataStack?
 }
diff --git a/Sources/CoreStoreManagedObject.swift b/Sources/CoreStoreManagedObject.swift
index 896fc02..d663ecb 100644
--- a/Sources/CoreStoreManagedObject.swift
+++ b/Sources/CoreStoreManagedObject.swift
@@ -48,6 +48,6 @@ import Foundation
 
 private enum Static {
     
-    static let queue = DispatchQueue.concurrent("com.coreStore.coreStoreManagerObjectBarrierQueue")
+    static let queue = DispatchQueue.concurrent("com.coreStore.coreStoreManagerObjectBarrierQueue", qos: .userInteractive)
     static var cache: [ObjectIdentifier: [KeyPathString: Set<KeyPathString>]] = [:]
 }
diff --git a/Sources/CoreStoreSchema.swift b/Sources/CoreStoreSchema.swift
index 5fa8c26..7c976f3 100644
--- a/Sources/CoreStoreSchema.swift
+++ b/Sources/CoreStoreSchema.swift
@@ -254,7 +254,7 @@ public final class CoreStoreSchema: DynamicSchema {
     
     // MARK: Private
     
-    private static let barrierQueue = DispatchQueue.concurrent("com.coreStore.coreStoreDataModelBarrierQueue")
+    private static let barrierQueue = DispatchQueue.concurrent("com.coreStore.coreStoreDataModelBarrierQueue", qos: .userInteractive)
     
     private let allEntities: Set<DynamicEntity>
     
diff --git a/Sources/DataStack.swift b/Sources/DataStack.swift
index 962acf7..02807a5 100644
--- a/Sources/DataStack.swift
+++ b/Sources/DataStack.swift
@@ -440,8 +440,8 @@ public final class DataStack: Equatable {
     internal let rootSavingContext: NSManagedObjectContext
     internal let mainContext: NSManagedObjectContext
     internal let schemaHistory: SchemaHistory
-    internal let childTransactionQueue = DispatchQueue.serial("com.coreStore.dataStack.childTransactionQueue")
-    internal let storeMetadataUpdateQueue = DispatchQueue.concurrent("com.coreStore.persistentStoreBarrierQueue")
+    internal let childTransactionQueue = DispatchQueue.serial("com.coreStore.dataStack.childTransactionQueue", qos: .utility)
+    internal let storeMetadataUpdateQueue = DispatchQueue.concurrent("com.coreStore.persistentStoreBarrierQueue", qos: .userInteractive)
     internal let migrationQueue: OperationQueue = Internals.with {
         
         let migrationQueue = OperationQueue()
diff --git a/Sources/DispatchQueue+CoreStore.swift b/Sources/DispatchQueue+CoreStore.swift
index 2987cbb..195d05a 100644
--- a/Sources/DispatchQueue+CoreStore.swift
+++ b/Sources/DispatchQueue+CoreStore.swift
@@ -31,7 +31,7 @@ import Foundation
 extension DispatchQueue {
     
     @nonobjc @inline(__always)
-    internal static func serial(_ label: String, qos: DispatchQoS = .default) -> DispatchQueue {
+    internal static func serial(_ label: String, qos: DispatchQoS) -> DispatchQueue {
         
         return DispatchQueue(
             label: label,
@@ -43,7 +43,7 @@ extension DispatchQueue {
     }
     
     @nonobjc @inline(__always)
-    internal static func concurrent(_ label: String, qos: DispatchQoS = .default) -> DispatchQueue {
+    internal static func concurrent(_ label: String, qos: DispatchQoS) -> DispatchQueue {
         
         return DispatchQueue(
             label: label,