diff --git a/include/uv/win.h b/include/uv/win.h
index 582d2e87..d2f69ccf 100644
--- a/include/uv/win.h
+++ b/include/uv/win.h
@@ -343,9 +343,9 @@ typedef struct {
   uv_idle_t* next_idle_handle;                                                \
   /* This handle holds the peer sockets for the fast variant of uv_poll_t */  \
   SOCKET poll_peer_sockets[UV_MSAFD_PROVIDER_COUNT];                          \
-  /* Counter to keep track of active tcp streams */                           \
+  /* No longer used. */                                                       \
   unsigned int active_tcp_streams;                                            \
-  /* Counter to keep track of active udp streams */                           \
+  /* No longer used. */                                                       \
   unsigned int active_udp_streams;                                            \
   /* Counter to started timer */                                              \
   uint64_t timer_counter;                                                     \
diff --git a/src/win/core.c b/src/win/core.c
index 67af93e6..8d4bbefd 100644
--- a/src/win/core.c
+++ b/src/win/core.c
@@ -279,9 +279,6 @@ int uv_loop_init(uv_loop_t* loop) {
 
   memset(&loop->poll_peer_sockets, 0, sizeof loop->poll_peer_sockets);
 
-  loop->active_tcp_streams = 0;
-  loop->active_udp_streams = 0;
-
   loop->timer_counter = 0;
   loop->stop_flag = 0;
 
diff --git a/src/win/tcp.c b/src/win/tcp.c
index f061ed76..20b03947 100644
--- a/src/win/tcp.c
+++ b/src/win/tcp.c
@@ -29,14 +29,6 @@
 #include "req-inl.h"
 
 
-/*
- * Threshold of active tcp streams for which to preallocate tcp read buffers.
- * (Due to node slab allocator performing poorly under this pattern,
- *  the optimization is temporarily disabled (threshold=0).  This will be
- *  revisited once node allocator is improved.)
- */
-const unsigned int uv_active_tcp_streams_threshold = 0;
-
 /*
  * Number of simultaneous pending AcceptEx calls.
  */
@@ -273,7 +265,6 @@ void uv__tcp_endgame(uv_loop_t* loop, uv_tcp_t* handle) {
   }
 
   uv__handle_close(handle);
-  loop->active_tcp_streams--;
 }
 
 
@@ -483,26 +474,9 @@ static void uv__tcp_queue_read(uv_loop_t* loop, uv_tcp_t* handle) {
   req = &handle->read_req;
   memset(&req->u.io.overlapped, 0, sizeof(req->u.io.overlapped));
 
-  /*
-   * Preallocate a read buffer if the number of active streams is below
-   * the threshold.
-  */
-  if (loop->active_tcp_streams < uv_active_tcp_streams_threshold) {
-    handle->flags &= ~UV_HANDLE_ZERO_READ;
-    handle->tcp.conn.read_buffer = uv_buf_init(NULL, 0);
-    handle->alloc_cb((uv_handle_t*) handle, 65536, &handle->tcp.conn.read_buffer);
-    if (handle->tcp.conn.read_buffer.base == NULL ||
-        handle->tcp.conn.read_buffer.len == 0) {
-      handle->read_cb((uv_stream_t*) handle, UV_ENOBUFS, &handle->tcp.conn.read_buffer);
-      return;
-    }
-    assert(handle->tcp.conn.read_buffer.base != NULL);
-    buf = handle->tcp.conn.read_buffer;
-  } else {
-    handle->flags |= UV_HANDLE_ZERO_READ;
-    buf.base = (char*) &uv_zero_;
-    buf.len = 0;
-  }
+  handle->flags |= UV_HANDLE_ZERO_READ;
+  buf.base = (char*) &uv_zero_;
+  buf.len = 0;
 
   /* Prepare the overlapped structure. */
   memset(&(req->u.io.overlapped), 0, sizeof(req->u.io.overlapped));
@@ -715,8 +689,6 @@ int uv__tcp_accept(uv_tcp_t* server, uv_tcp_t* client) {
     }
   }
 
-  loop->active_tcp_streams++;
-
   return err;
 }
 
@@ -1247,7 +1219,6 @@ void uv__process_tcp_connect_req(uv_loop_t* loop, uv_tcp_t* handle,
                           0) == 0) {
       uv__connection_init((uv_stream_t*)handle);
       handle->flags |= UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
-      loop->active_tcp_streams++;
     } else {
       err = WSAGetLastError();
     }
@@ -1330,7 +1301,6 @@ int uv__tcp_xfer_import(uv_tcp_t* tcp,
     tcp->flags |= UV_HANDLE_READABLE | UV_HANDLE_WRITABLE;
   }
 
-  tcp->loop->active_tcp_streams++;
   return 0;
 }
 
diff --git a/src/win/udp.c b/src/win/udp.c
index eaebc1ed..1edb7f62 100644
--- a/src/win/udp.c
+++ b/src/win/udp.c
@@ -29,11 +29,6 @@
 #include "req-inl.h"
 
 
-/*
- * Threshold of active udp streams for which to preallocate udp read buffers.
- */
-const unsigned int uv_active_udp_streams_threshold = 0;
-
 /* A zero-size buffer for use by uv_udp_read */
 static char uv_zero_[] = "";
 int uv_udp_getpeername(const uv_udp_t* handle,
@@ -276,84 +271,35 @@ static void uv__udp_queue_recv(uv_loop_t* loop, uv_udp_t* handle) {
   req = &handle->recv_req;
   memset(&req->u.io.overlapped, 0, sizeof(req->u.io.overlapped));
 
-  /*
-   * Preallocate a read buffer if the number of active streams is below
-   * the threshold.
-  */
-  if (loop->active_udp_streams < uv_active_udp_streams_threshold) {
-    handle->flags &= ~UV_HANDLE_ZERO_READ;
+  handle->flags |= UV_HANDLE_ZERO_READ;
 
-    handle->recv_buffer = uv_buf_init(NULL, 0);
-    handle->alloc_cb((uv_handle_t*) handle, UV__UDP_DGRAM_MAXSIZE, &handle->recv_buffer);
-    if (handle->recv_buffer.base == NULL || handle->recv_buffer.len == 0) {
-      handle->recv_cb(handle, UV_ENOBUFS, &handle->recv_buffer, NULL, 0);
-      return;
-    }
-    assert(handle->recv_buffer.base != NULL);
+  buf.base = (char*) uv_zero_;
+  buf.len = 0;
+  flags = MSG_PEEK;
 
-    buf = handle->recv_buffer;
-    memset(&handle->recv_from, 0, sizeof handle->recv_from);
-    handle->recv_from_len = sizeof handle->recv_from;
-    flags = 0;
-
-    result = handle->func_wsarecvfrom(handle->socket,
-                                      (WSABUF*) &buf,
-                                      1,
-                                      &bytes,
-                                      &flags,
-                                      (struct sockaddr*) &handle->recv_from,
-                                      &handle->recv_from_len,
-                                      &req->u.io.overlapped,
-                                      NULL);
-
-    if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
-      /* Process the req without IOCP. */
-      handle->flags |= UV_HANDLE_READ_PENDING;
-      req->u.io.overlapped.InternalHigh = bytes;
-      handle->reqs_pending++;
-      uv__insert_pending_req(loop, req);
-    } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
-      /* The req will be processed with IOCP. */
-      handle->flags |= UV_HANDLE_READ_PENDING;
-      handle->reqs_pending++;
-    } else {
-      /* Make this req pending reporting an error. */
-      SET_REQ_ERROR(req, WSAGetLastError());
-      uv__insert_pending_req(loop, req);
-      handle->reqs_pending++;
-    }
+  result = handle->func_wsarecv(handle->socket,
+                                (WSABUF*) &buf,
+                                1,
+                                &bytes,
+                                &flags,
+                                &req->u.io.overlapped,
+                                NULL);
 
+  if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
+    /* Process the req without IOCP. */
+    handle->flags |= UV_HANDLE_READ_PENDING;
+    req->u.io.overlapped.InternalHigh = bytes;
+    handle->reqs_pending++;
+    uv__insert_pending_req(loop, req);
+  } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
+    /* The req will be processed with IOCP. */
+    handle->flags |= UV_HANDLE_READ_PENDING;
+    handle->reqs_pending++;
   } else {
-    handle->flags |= UV_HANDLE_ZERO_READ;
-
-    buf.base = (char*) uv_zero_;
-    buf.len = 0;
-    flags = MSG_PEEK;
-
-    result = handle->func_wsarecv(handle->socket,
-                                  (WSABUF*) &buf,
-                                  1,
-                                  &bytes,
-                                  &flags,
-                                  &req->u.io.overlapped,
-                                  NULL);
-
-    if (UV_SUCCEEDED_WITHOUT_IOCP(result == 0)) {
-      /* Process the req without IOCP. */
-      handle->flags |= UV_HANDLE_READ_PENDING;
-      req->u.io.overlapped.InternalHigh = bytes;
-      handle->reqs_pending++;
-      uv__insert_pending_req(loop, req);
-    } else if (UV_SUCCEEDED_WITH_IOCP(result == 0)) {
-      /* The req will be processed with IOCP. */
-      handle->flags |= UV_HANDLE_READ_PENDING;
-      handle->reqs_pending++;
-    } else {
-      /* Make this req pending reporting an error. */
-      SET_REQ_ERROR(req, WSAGetLastError());
-      uv__insert_pending_req(loop, req);
-      handle->reqs_pending++;
-    }
+    /* Make this req pending reporting an error. */
+    SET_REQ_ERROR(req, WSAGetLastError());
+    uv__insert_pending_req(loop, req);
+    handle->reqs_pending++;
   }
 }
 
@@ -376,7 +322,6 @@ int uv__udp_recv_start(uv_udp_t* handle, uv_alloc_cb alloc_cb,
 
   handle->flags |= UV_HANDLE_READING;
   INCREASE_ACTIVE_COUNT(loop, handle);
-  loop->active_udp_streams++;
 
   handle->recv_cb = recv_cb;
   handle->alloc_cb = alloc_cb;
@@ -393,7 +338,6 @@ int uv__udp_recv_start(uv_udp_t* handle, uv_alloc_cb alloc_cb,
 int uv__udp_recv_stop(uv_udp_t* handle) {
   if (handle->flags & UV_HANDLE_READING) {
     handle->flags &= ~UV_HANDLE_READING;
-    handle->loop->active_udp_streams--;
     DECREASE_ACTIVE_COUNT(loop, handle);
   }