SumProductBenchmark.cs

public class SumProductBenchmark : IDisposable
{
    private readonly XLWorkbook _wb;
    private readonly IXLWorksheet _ws;

    [Params(1000, 10000, 100000)]
    public int RowsCount;

    public SumProductBenchmark()
    {
        _wb = new XLWorkbook();
        _ws = _wb.AddWorksheet();
    }

    [GlobalSetup]
    public void Setup()
    {
        _ws.Cell("A1").InsertData(Enumerable.Range(1, RowsCount));
        _ws.Cell("B1").InsertData(Enumerable.Range(1, RowsCount).Reverse());
        _ws.Cell("C1").InsertData(Enumerable.Range(1, RowsCount));
        _ws.Cell("D1").InsertData(Enumerable.Range(1, RowsCount).Reverse());
    }

    [Benchmark]
    public XLCellValue SumProduct() => _ws.Evaluate($"SUMPRODUCT(A1:B{RowsCount}, C1:D{RowsCount})");

    [Benchmark]
    public XLCellValue LegacySumProduct() => _ws.Evaluate($"SUMPRODUCT.LEGACY(A1:B{RowsCount}, C1:D{RowsCount})");

    public void Dispose() => _wb.Dispose();
}