diff --git a/kernel/common/time.rb b/kernel/common/time.rb
index 05534db..174e5da 100644
--- a/kernel/common/time.rb
+++ b/kernel/common/time.rb
@@ -54,6 +54,10 @@ class Time
     :usec => 1,
   }
 
+  def initialize
+    gettimeofday
+  end
+
   #--
   # TODO: doesn't load nsec or ivars
   #++
@@ -91,6 +95,8 @@ class Time
   #++
 
   def _dump(limit = nil)
+    build_tm
+
     tm = @tm
     is_gmt = @is_gmt
 
@@ -148,7 +154,7 @@ class Time
 
     t = Time.allocate
     t.mktime(second, minute, hour, day, month, year, usec, isdst, false)
-    t.force_localtime
+    t
   end
 
   def self.gm(first, *args)
@@ -178,7 +184,7 @@ class Time
 
     t = Time.allocate
     t.mktime(second, minute, hour, day, month, year, usec, -1, true)
-    t.force_gmtime
+    t
   end
 
   def self.at(secs_or_time, msecs = nil)
@@ -190,10 +196,14 @@ class Time
   end
 
   def strftime(format)
+    build_tm
+
     __strftime__(@tm, format.to_str)
   end
 
   def inspect
+    build_tm
+
     if @is_gmt
       strftime("%a %b %d %H:%M:%S UTC %Y")
     else
@@ -251,30 +261,44 @@ class Time
   end
 
   def hour
+    build_tm
+
     @tm[2]
   end
 
   def min
+    build_tm
+
     @tm[1]
   end
 
   def sec
+    build_tm
+
     @tm[0]
   end
 
   def day
+    build_tm
+
     @tm[3]
   end
 
   def year
+    build_tm
+
     @tm[5] + 1900
   end
 
   def yday
+    build_tm
+
     @tm[7] + 1
   end
 
   def wday
+    build_tm
+
     @tm[6]
   end
 
@@ -283,6 +307,8 @@ class Time
   end
 
   def mon
+    build_tm
+
     @tm[4] + 1
   end
 
@@ -336,18 +362,26 @@ class Time
   end
 
   def localtime
-    force_localtime if @is_gmt
+    if @is_gmt
+      @is_gmt = false
+      @has_tm = false
+    end
 
     self
   end
 
   def gmtime
-    force_gmtime unless @is_gmt
+    unless @is_gmt
+      @is_gmt = true
+      @has_tm = false
+    end
 
     self
   end
 
   def dst?
+    build_tm
+
     !@tm[8].zero?
   end
 
@@ -363,20 +397,6 @@ class Time
     seconds ^ usec
   end
 
-  def force_localtime
-    time_switch false
-    @is_gmt = false
-
-    self
-  end
-
-  def force_gmtime
-    time_switch true
-    @is_gmt = true
-
-    self
-  end
-
   def mktime(sec, min, hour, mday, mon, year, usec, isdst, from_gmt)
     sec  = sec.to_i
     min  = min.to_i
@@ -398,6 +418,8 @@ class Time
     end
 
     @timeval = time_mktime(sec, min, hour, mday, mon, year, usec, isdst, from_gmt)
+    @is_gmt = from_gmt
+
     raise ArgumentError, "time out of range" if @timeval.first == -1
 
     self
@@ -422,11 +444,15 @@ class Time
     usec = usec % 1000000
 
     @timeval = [sec, usec]
+    @is_gmt = want_gmt
+    @has_tm = false
 
-    if want_gmt
-      force_gmtime
-    else
-      force_localtime
+    self
+  end
+
+  def build_tm
+    unless @has_tm
+      time_switch @is_gmt
     end
   end
 
diff --git a/vm/builtin/time.cpp b/vm/builtin/time.cpp
index 5cbca71..a5f83c1 100644
--- a/vm/builtin/time.cpp
+++ b/vm/builtin/time.cpp
@@ -22,8 +22,14 @@ namespace rubinius {
   Time* Time::create(STATE) {
     Time* tm = state->new_object<Time>(G(time_class));
 
-    tm->gettimeofday(state);
-    tm->time_switch(state, Qfalse);
+    /* update Time::TIMEVAL_FIELDS when changing order of fields */
+    Array* ary = Array::create(state, 2);
+    ary->set(state, 0, Integer::from(state, 0));
+    ary->set(state, 1, Integer::from(state, 0));
+
+    tm->timeval(state, ary);
+    tm->has_tm(state, Qfalse);
+    tm->is_gmt(state, Qfalse);
 
     return tm;
   }
@@ -44,11 +50,8 @@ namespace rubinius {
     ::gettimeofday(&tv, NULL);
 
     /* update Time::TIMEVAL_FIELDS when changing order of fields */
-    Array* ary = Array::create(state, 2);
-    ary->set(state, 0, Integer::from(state, tv.tv_sec));
-    ary->set(state, 1, Integer::from(state, tv.tv_usec));
-
-    this->timeval(state, ary);
+    timeval_->set(state, 0, Integer::from(state, tv.tv_sec));
+    timeval_->set(state, 1, Integer::from(state, tv.tv_usec));
 
     return this;
   }
@@ -88,7 +91,7 @@ namespace rubinius {
 #endif
 
     this->tm(state, ary);
-    this->is_gmt(state, gmt);
+    this->has_tm(state, Qtrue);
 
     return this;
   }
diff --git a/vm/builtin/time.hpp b/vm/builtin/time.hpp
index 4749671..bc0bb9e 100644
--- a/vm/builtin/time.hpp
+++ b/vm/builtin/time.hpp
@@ -21,6 +21,7 @@ namespace rubinius {
     Array* timeval_; // slot
     Array* tm_;      // slot
     Object* is_gmt_;  // slot
+    Object* has_tm_;  // slot
 
   public:
     /* accessors */
@@ -28,6 +29,7 @@ namespace rubinius {
     attr_accessor(timeval, Array);
     attr_accessor(tm, Array);
     attr_accessor(is_gmt, Object);
+    attr_accessor(has_tm, Object);
 
     /* interface */