Efficiency: member variable vs local variable in a timer

Question

I could not find similar questions here, so I am posting new one. In c# program with timer, what is more efficient:

1. Declaring member variable, then using with each timer tick, it to calculate and change its value, or
2. Declaring local variable inside a timer_tick routine, and declaring it each time, recalculating, using it, and then with next tick - doing it all over again ?

Example code:

ClassOne
{
    float mVar1 = 0;

    Timer_Tick
    {
        mVar1 += CurrentSpeed;
        SpeedOfSomething = mVar1;
    }
}

OR:

ClassOne
{
    Timer_Tick
    {
        float Var1 = 0;
        Var1 += CurrentSpeed;
        SpeedOfSomething = Var1;
    }
}

Answer 1

in the second one:

 Timer_Tick
    {
        float Var1 = 0;
        Var1 += CurrentSpeed;
        SpeedOfSomething = Var1;
    }

Every time that Timer_Tick is fired, float Var1 = 0; will be executed and actually Var1 value will always be 0. So its not a correct solution.