Heavy I/O for Microsoft Transaction Log
Thing i would do to make the transactionlog faster.


Check NTFS block size, and reformat drive to 64k
Check VLF's (should warn in EXEC xp_readerrorlog) if you above 1k.. shrink/grow file to fix.
Set sensible log-file growth rates (not 1% or 1MB)
Consider using Delayed Durability where its possible (be mindfull of Data integrity/DR)


The all-knowing K. Tripp has an article on this
http://www.sqlskills.com/blogs/kimberly/8-steps-to-better-transaction-log-throughput/