transferring calculations from Excel to VBA (to save calculation time)

[buffalo]

I have a contiguous range of rows starting from B5 and could end anywhere below.
Now cell A1 has the formula "=if(B1="","",Pricer(B1, C1, D1))" etc. and it goes on upto A20000.
Instead of this I need only values in A1:A20000 based on above formula. All calculation is to be done in VBA without doing .Formula = "=Pricer…etc " and then doing .value = .value
Thanks in advance

** Pricer is an add-in based function and the purpose of moving to background calculation in VBA is to save time. For purposes of illustration you may use the function SQRT(B2*C2*D2) to replicate the function Pricer(B1,C1,D1)

[shg]

Why not set calculation to manual and calculate as needed?