Libreoffice 6 calc: speed up vlookup, match, index search


I have installed libreoffice under ubuntu mate 16.04 64 bit. I have a calc file with 35 sheets. In particular, one sheet is made of about 500 rows and about 50 columns.

The sheet has 2 columns with match and index and 1 column with vlookup while the other are simple formulas as countif, count and four operations.

When I add a new row or when I change one value in a cell that requires to update the entire row, the update is extremely slow about 60 seconds. The same when I save the file.

My formulas are:

Nested match, index


Nested index, match, index


Standard vlookup


I disabled openGL, experimental features and search criteria via:

calc/Calculate - Searc criteria = and
<> must apply to whole cells.

Unfortunately, I cannot speed the process. I tried also to copy this sheet into a new empty file, but the result is more or less the same. I cannot use openCL since it is not supported by GPU and enabling or disabling it does not make any effect.

What can I do in order to make usable the sheet?

Thank you

I have i7-3537U CPU with 8 GB DDR3 1600 MHz RAM and EVO 850 SSD.

I followed this guide and now the OS recognizes my openCL v1.2 compatible CPU Intel(R) HD Graphics IvyBridge M GT2.
However, libreoffice disable each time openCL from the options.