How to allow SQL Server Express to use multiple cores?

I am currently doing load testing and sqlservr.exe during peak times is using only up to 50% of CPU.

Is there a way to force Sql Server to use more than 50% of CPU?

I am r开发者_高级运维unning virtual machine on GoGrid with 2GBs of RAM (2 cores), SQL Server is Express Edition 2008 R2.

Thanks in advance!

SQL Server Express edition is limited to a single processor.

Edit: MSDN Reference

Please make sure that the virtual machine is set to use all available cpu cores.