diff --git a/tuic-client/README.md b/tuic-client/README.md
index ddb7629..b814a4e 100644
--- a/tuic-client/README.md
+++ b/tuic-client/README.md
@@ -89,13 +89,13 @@ tuic-client -c PATH/TO/CONFIG
 
         // Optional. Maximum number of bytes to transmit to a peer without acknowledgment
         // Should be set to at least the expected connection latency multiplied by the maximum desired throughput
-        // Default: 16MiB * 2
-        "send_window": 33554432,
+        // Default: 8MiB * 2
+        "send_window": 16777216,
 
         // Optional. Maximum number of bytes the peer may transmit without acknowledgement on any one stream before becoming blocked
         // Should be set to at least the expected connection latency multiplied by the maximum desired throughput
-        // Default: 16MiB
-        "receive_window": 16777216,
+        // Default: 8MiB
+        "receive_window": 8388608,
 
         // Optional. Interval between UDP packet fragment garbage collection
         // Default: 3s
diff --git a/tuic-client/src/config.rs b/tuic-client/src/config.rs
index 81f38d5..60a27e9 100644
--- a/tuic-client/src/config.rs
+++ b/tuic-client/src/config.rs
@@ -197,11 +197,11 @@ mod default {
         }
 
         pub fn send_window() -> u64 {
-            2u64.pow(24) * 2
+            8 * 1024 * 1024 * 2
         }
 
         pub fn receive_window() -> u32 {
-            2u32.pow(24)
+            8 * 1024 * 1024
         }
 
         pub fn gc_interval() -> Duration {
diff --git a/tuic-server/README.md b/tuic-server/README.md
index 2da0a2f..49ac0df 100644
--- a/tuic-server/README.md
+++ b/tuic-server/README.md
@@ -81,13 +81,13 @@ tuic-server -c PATH/TO/CONFIG
 
     // Optional. Maximum number of bytes to transmit to a peer without acknowledgment
     // Should be set to at least the expected connection latency multiplied by the maximum desired throughput
-    // Default: 16MiB * 2
-    "send_window": 33554432,
+    // Default: 8MiB * 2
+    "send_window": 16777216,
 
     // Optional. Maximum number of bytes the peer may transmit without acknowledgement on any one stream before becoming blocked
     // Should be set to at least the expected connection latency multiplied by the maximum desired throughput
-    // Default: 16MiB
-    "receive_window": 16777216,
+    // Default: 8MiB
+    "receive_window": 8388608,
 
     // Optional. Interval between UDP packet fragment garbage collection
     // Default: 3s
diff --git a/tuic-server/src/config.rs b/tuic-server/src/config.rs
index eceee6b..f10f1a7 100644
--- a/tuic-server/src/config.rs
+++ b/tuic-server/src/config.rs
@@ -161,11 +161,11 @@ mod default {
     }
 
     pub fn send_window() -> u64 {
-        2u64.pow(24) * 2
+        8 * 1024 * 1024 * 2
     }
 
     pub fn receive_window() -> u32 {
-        2u32.pow(24)
+        8 * 1024 * 1024
     }
 
     pub fn gc_interval() -> Duration {