diff --git a/lib/dust.js b/lib/dust.js
index cccc35f8..4e8d067d 100755
--- a/lib/dust.js
+++ b/lib/dust.js
@@ -181,8 +181,8 @@ Context.prototype.current = function() {
 
 Context.prototype.getBlock = function(key, chk, ctx) {
   if (typeof key === "function") {
-    key = key(chk, ctx).data;
-    chk.data = "";
+    key = key(chk, ctx).data.join("");
+    chk.data = []; //ie7 perf
   }
 
   var blocks = this.blocks;
@@ -229,7 +229,7 @@ Stub.prototype.flush = function() {
 
   while (chunk) {
     if (chunk.flushable) {
-      this.out += chunk.data;
+      this.out += chunk.data.join(""); //ie7 perf
     } else if (chunk.error) {
       this.callback(chunk.error);
       this.flush = function() {};
@@ -252,7 +252,7 @@ Stream.prototype.flush = function() {
 
   while(chunk) {
     if (chunk.flushable) {
-      this.emit('data', chunk.data);
+      this.emit('data', chunk.data.join("")); //ie7 perf
     } else if (chunk.error) {
       this.emit('error', chunk.error);
       this.flush = function() {};
@@ -308,7 +308,7 @@ Stream.prototype.pipe = function(stream) {
 function Chunk(root, next, taps) {
   this.root = root;
   this.next = next;
-  this.data = '';
+  this.data = []; //ie7 perf
   this.flushable = false;
   this.taps = taps;
 }
@@ -319,7 +319,7 @@ Chunk.prototype.write = function(data) {
   if (taps) {
     data = taps.go(data);
   }
-  this.data += data;
+  this.data.push(data);
   return this;
 };
 
diff --git a/test/uutest.js b/test/uutest.js
index 79aa7a82..97415e46 100644
--- a/test/uutest.js
+++ b/test/uutest.js
@@ -20,11 +20,11 @@ Test.prototype.run = function() {
 }
 
 Test.prototype.equals = function(actual, expected, message) {
-  if (actual !== expected) {
-    var err = new Error();
-    if (message) err.message = message;
-    throw wrapAssertionError(err, actual, expected, "===");
-  }
+    if (actual !== expected) {
+        var err = new Error();
+        if (message) err.message = message;
+        throw wrapAssertionError(err, actual, expected, "===");
+    }
 }
 
 Test.prototype.ifError = function(err) {