Crash database, need some advices

Hello,
I am developing a penny auction website with wordpress and we had tested our site and the website crashed during the test under the load. While the server coped fine, the issue came with the database failing. The server we have opted for is a rather powerful one which would handle this level of traffic quite readily.

I am wondering if I should find another script (software) which will be costly or is there any way to optimise the wp database and avoid any crash in the future?

Is wordpress not suitable for this type of website?

Thank you very much for your help!