It sounds like you've nailed it. The customer base for Tableau is so diverse that while 8 million rows is nothing to scoff at, many users have much more data and are able to successfully leverage Tableau. My guess is that you may have too little RAM, as Tableau loads data in-memory for performance. Could you share your tech specs?
Christian Trautner, can you be more specific what does not work or perform?
From my experience, row count (8M) is on the low side, column count (567) is a bit outside of what we typically see however it is still something that we should be able to handle.
Where is the data located (file? database?) and can you connect to it? How many tables is it?
Can you preview the data on Data Source tab?
Can you build a simple viz?