SQL Server: Has anyone used the large-page allocations tuning option?

Thomas Kejser from Microsoft (blog) regularly presents that the 834 trace flag is the only go-faster trace flag for SQL Server. He would caveat that, I'm sure, with plenty of testing!

Difficult question. What I have opened for myself and, I hope, you will find out something new:

Trace flag 834: Use Microsoft Windows large-page allocations for the buffer pool Trace flag 834 causes SQL Server to use Microsoft Windows large-page allocations for the memory that is allocated for the buffer pool. The page size varies depending on the hardware platform, but the page size may be from 2 MB to 16 MB. Large pages are allocated at startup and are kept throughout the lifetime of the process. Trace flag 834 improves performance by increasing the efficiency of the translation look-aside buffer (TLB) in the CPU.

Trace flag 834 applies only to 64-bit versions of SQL Server. You must have the Lock pages in memory user right to turn on trace flag 834. You can turn on trace flag 834 only at startup.

Trace flag 834 may prevent the server from starting if memory is fragmented and if large pages cannot be allocated. Therefore, trace flag 834 is best suited for servers that are dedicated to SQL Server. more

On my opinion, it is a good enough (and ONLY) documents: Troubleshooting Performance Problems in SQL Server 2005 and for SQL Server 2008: Troubleshooting Performance Problems in SQL Server 2008. Two words about Denali and what is new: SQL Server Memory manager changes in Denali.

Luck.