// 1) Delete column by column
for(ii=101; ii<=600; ii++) {
  range rc=[Book2]1!col(101);
  delete rc;
}
//==> 337 seconds

// 2) Delete a block of columns
range rd = [Book2]Sheet1!101:600;
delete rd;
//==> 172 seconds

// 3) Copy columns (then delete original workbook)
wrcopy iw:=[Book1]sheet1! c1:=1 c2:=100 label:=1 ow:=[Book2]sheet1!;
wrcopy iw:=[Book1]sheet1! c1:=601 c2:=1300 dc1:=101 label:=1 ow:=[Book2]sheet1!;
//window -cd Book1; //delete original workbook
//==>0.375 seconds

// 4) Hide instead of delete columns
colhide irng:=col(101):col(600) operation:=hide;
//==>0.015 seconds