diff --git a/.changeset/eight-hotels-try.md b/.changeset/eight-hotels-try.md
new file mode 100644
index 000000000000..f1fab2897d1f
--- /dev/null
+++ b/.changeset/eight-hotels-try.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Disables streaming when rendering site with `output: "static"`
diff --git a/packages/astro/src/core/build/pipeline.ts b/packages/astro/src/core/build/pipeline.ts
index a89aa10f071c..245904660c18 100644
--- a/packages/astro/src/core/build/pipeline.ts
+++ b/packages/astro/src/core/build/pipeline.ts
@@ -53,7 +53,8 @@ export class BuildPipeline extends Pipeline {
 			return assetLink;
 		}
 		const serverLike = isServerLikeOutput(config);
-		const streaming = true;
+		// We can skip streaming in SSG for performance as writing as strings are faster
+		const streaming = serverLike;
 		super(
 			options.logger,
 			manifest,
diff --git a/packages/astro/src/runtime/server/render/astro/render.ts b/packages/astro/src/runtime/server/render/astro/render.ts
index 37a78725a092..f918f55c11dc 100644
--- a/packages/astro/src/runtime/server/render/astro/render.ts
+++ b/packages/astro/src/runtime/server/render/astro/render.ts
@@ -31,6 +31,10 @@ export async function renderToString(
 	let str = '';
 	let renderedFirstPageChunk = false;
 
+	if (isPage) {
+		await bufferHeadContent(result);
+	}
+
 	const destination: RenderDestination = {
 		write(chunk) {
 			// Automatic doctype insertion for pages
diff --git a/packages/astro/test/content-collections-render.test.js b/packages/astro/test/content-collections-render.test.js
index 0e8e37fb176b..277ef8c06956 100644
--- a/packages/astro/test/content-collections-render.test.js
+++ b/packages/astro/test/content-collections-render.test.js
@@ -2,11 +2,7 @@ import * as assert from 'node:assert/strict';
 import { after, before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import testAdapter from './test-adapter.js';
-import { isWindows, loadFixture } from './test-utils.js';
-
-if (!isWindows) {
-	describe();
-}
+import { loadFixture } from './test-utils.js';
 
 describe('Content Collections - render()', () => {
 	describe('Build - SSG', () => {