diff --git a/packages/ai/src/generate-text/stream-text.ts b/packages/ai/src/generate-text/stream-text.ts
index 3be48634721d..4e6a869ec761 100644
--- a/packages/ai/src/generate-text/stream-text.ts
+++ b/packages/ai/src/generate-text/stream-text.ts
@@ -629,6 +629,7 @@ function createOutputTransformStream<
   let textChunk = '';
   let textProviderMetadata: ProviderMetadata | undefined = undefined;
   let lastPublishedJson = '';
+  const isTextOutput = output.name === 'text';
 
   function publishTextChunk({
     controller,
@@ -696,6 +697,17 @@ function createOutputTransformStream<
       textChunk += chunk.text;
       textProviderMetadata = chunk.providerMetadata ?? textProviderMetadata;
 
+      // For text output, every text-delta always changes the partial output,
+      // so we can publish immediately and avoid the expensive JSON.stringify
+      // comparison that causes O(n²) memory growth with large responses.
+      if (isTextOutput) {
+        publishTextChunk({
+          controller,
+          partialOutput: text as InferPartialOutput<OUTPUT>,
+        });
+        return;
+      }
+
       // only publish if partial json can be parsed:
       const result = await output.parsePartialOutput({ text });