diff --git a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/HqInteropGetClient.kt b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/HqInteropGetClient.kt
index a1745efb06..10c249c9f8 100644
--- a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/HqInteropGetClient.kt
+++ b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/HqInteropGetClient.kt
@@ -21,6 +21,7 @@
 package com.vitorpamplona.quic.interop.runner
 
 import com.vitorpamplona.quic.connection.QuicConnection
+import com.vitorpamplona.quic.connection.QuicConnectionDriver
 import kotlinx.coroutines.flow.toList
 
 /**
@@ -38,6 +39,7 @@ import kotlinx.coroutines.flow.toList
  */
 class HqInteropGetClient(
     private val conn: QuicConnection,
+    private val driver: QuicConnectionDriver,
 ) : GetClient {
     override suspend fun get(
         @Suppress("UNUSED_PARAMETER") authority: String,
@@ -47,6 +49,8 @@ class HqInteropGetClient(
         val request = "GET $path\r\n".encodeToByteArray()
         stream.send.enqueue(request)
         stream.send.finish()
+        // Nudge the send loop — see Http3GetClient.get for rationale.
+        driver.wakeup()
 
         val chunks = stream.incoming.toList()
         val total = chunks.sumOf { it.size }
diff --git a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/Http3GetClient.kt b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/Http3GetClient.kt
index 734be314a0..ca2571d840 100644
--- a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/Http3GetClient.kt
+++ b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/Http3GetClient.kt
@@ -22,6 +22,7 @@ package com.vitorpamplona.quic.interop.runner
 
 import com.vitorpamplona.quic.QuicWriter
 import com.vitorpamplona.quic.connection.QuicConnection
+import com.vitorpamplona.quic.connection.QuicConnectionDriver
 import com.vitorpamplona.quic.connection.drainPeerInitiatedUniStreamsIntoBlackHole
 import com.vitorpamplona.quic.http3.Http3Frame
 import com.vitorpamplona.quic.http3.Http3FrameReader
@@ -60,6 +61,7 @@ data class GetResponse(
  */
 class Http3GetClient(
     private val conn: QuicConnection,
+    private val driver: QuicConnectionDriver,
 ) : GetClient {
     suspend fun init(scope: CoroutineScope) {
         // Control stream: type-0x00 prefix followed by a SETTINGS frame
@@ -111,6 +113,11 @@ class Http3GetClient(
         val stream = conn.openBidiStream()
         stream.send.enqueue(encodeRequest(authority, path))
         stream.send.finish()
+        // Nudge the send loop. Without this it suspends until PTO (~1s)
+        // or until an inbound packet arrives. For the multiplexing path
+        // this was the dominant throughput bottleneck — chunks of 64
+        // requests sat idle for ~1s each waiting to be drained.
+        driver.wakeup()
 
         val reader = Http3FrameReader()
         var status = 0
diff --git a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/InteropClient.kt b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/InteropClient.kt
index 5532186659..40bab3887a 100644
--- a/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/InteropClient.kt
+++ b/quic/interop/src/main/kotlin/com/vitorpamplona/quic/interop/runner/InteropClient.kt
@@ -291,16 +291,16 @@ private fun runTransferTest(
             val client: GetClient =
                 when (negotiated) {
                     "h3" -> {
-                        Http3GetClient(conn).also { it.init(scope) }
+                        Http3GetClient(conn, driver).also { it.init(scope) }
                     }
 
                     "hq-interop" -> {
-                        HqInteropGetClient(conn)
+                        HqInteropGetClient(conn, driver)
                     }
 
                     else -> {
                         System.err.println("unrecognized negotiated ALPN '$negotiated'; defaulting to hq-interop")
-                        HqInteropGetClient(conn)
+                        HqInteropGetClient(conn, driver)
                     }
                 }