var spread = new GcSpread.Sheets.Spread(document.getElementById('ss'), { sheetCount: 1 });

var sheet = spread.getActiveSheet();


sheet.setRowCount(2005);

sheet.isPaintSuspended(true);

sheet.suspendEvent();

sheet.suspendCalcService();

for (var i = 1; i < 2000; i++) {

    for (var j = 1; j < 21;j++) {

        sheet.setFormula(i, j, 'A1+A'+ (i + 1) + '+' + String.fromCharCode(j + 65) + '1');

    }

}  

sheet.resumeCalcService();

sheet.resumeEvent();

sheet.isPaintSuspended(false);

then:

var spread = new GcSpread.Sheets.Spread(document.getElementById('ss'), { sheetCount: 1 });

var sheet = spread.getActiveSheet();


sheet.setRowCount(2005);

sheet.isPaintSuspended(true);

sheet.suspendEvent();

sheet.suspendCalcService();

for (var i = 1; i < 2000; i++) {

    for (var j = 1; j < 21;j++) {

        sheet.setFormula(i, j, 'A1+A'+ (i + 1) + '+' + String.fromCharCode(j + 65) + '1');

    }

}  

sheet.resumeCalcService();

sheet.resumeEvent();

sheet.isPaintSuspended(false);