--- src/sdl/i_system.cpp    2014-09-07 14:15:44.000000000 +0000
+++ src/sdl/i_system.cpp.new    2014-09-14 20:56:40.003386878 +0000
@@ -123,14 +123,13 @@ void I_EndRead(void)


 static DWORD TicStart;
-static DWORD TicNext;
 static DWORD BaseTime;
 static int TicFrozen;

 // Signal based timer.
 static Semaphore timerWait;
 static int tics;
-static DWORD sig_start, sig_next;
+static DWORD sig_start;

 void I_SelectTimer();

@@ -169,7 +168,6 @@ int I_GetTimePolled (bool saveMS)
    if (saveMS)
    {
        TicStart = tm;
-       TicNext = Scale((Scale (tm, TICRATE, 1000) + 1), 1000, TICRATE);
    }
    return Scale(tm - BaseTime, TICRATE, 1000);
 }
@@ -179,7 +177,6 @@ int I_GetTimeSignaled (bool saveMS)
    if (saveMS)
    {
        TicStart = sig_start;
-       TicNext = sig_next;
    }
    return tics;
 }
@@ -250,7 +247,6 @@ void I_HandleAlarm (int sig)
    if(!TicFrozen)
        tics++;
    sig_start = SDL_GetTicks();
-   sig_next = Scale((Scale (sig_start, TICRATE, 1000) + 1), 1000, TICRATE);
    SEMAPHORE_SIGNAL(timerWait)
 }

@@ -293,15 +289,14 @@ void I_SelectTimer()
 fixed_t I_GetTimeFrac (uint32 *ms)
 {
    DWORD now = SDL_GetTicks ();
-   if (ms) *ms = TicNext;
-   DWORD step = TicNext - TicStart;
-   if (step == 0)
+   if (ms) *ms = TicStart + (1000 / TICRATE);
+   if (TicStart == 0)
    {
        return FRACUNIT;
    }
    else
    {
-       fixed_t frac = clamp<fixed_t> ((now - TicStart)*FRACUNIT/step, 0, FRACUNIT);
+       fixed_t frac = clamp<fixed_t> ((now - TicStart)*FRACUNIT*TICRATE/1000, 0, FRACUNIT);
        return frac;
    }
 }