Vaadin table performance

I'm prototyping Vaadin for use in our application but I'm hitting a performance problem with tables. If I have ~200 products in the result set and they are divided over a number of categories (and each category having a detail-table) I end up with a wall-clock-roundtrip of over 30 seconds(!).

The category header is a HorizontalLayout with two labels and a Table and the category products is a table. The number of items in the category header detail table is usually 1-3 and the products in a category 1-5. The total number of tables is around 300 which is sub-optimal but is there any way of optimizing performance (fixing withs etc)?

Thanks in advance,
  Nik

Even dropping the header information and using a Grid for the products takes ~20sec