jQuery Grid Plugin - jqGrid

I am seeing performance issues when grouping is introduced to the group.  Specifically, I have 1221 rows of data.  When I turn on grouping the page keeps giving me 'A script is taking to long' messages.  If I turn off grouping, then the page takes some time but renders without any messages.  At this point a non-vitrual scroll bar pager is not an option for my scenario.  Are there any recommendations?  I want to implement a virtual scroll bar pager, but as soon as grouping is added to the grid, then by default a non-scroll bar pager is added to the grid, so it looks like virtual scroll paging is not supported when grouping is included on the grid.

1. Are you aware of the performance issues when grouping is included on large datasets (around 100o rows)?

2. Is virtual scroll paging not supported when grouping is involved?

I look forward to your response.

Thank you.