How to scale my SQL Server 2008?
To take a different approach, what is driving your read workload - Is it the application, or do you have a bunch of reports hanging off the system that are driving the load?  Depending on the nature of your workload you might be able to re-shuffle your hardware or push some of it off onto other machines.

A couple of ideas:


If you have a lot of read workload driven by reports (as opposed to application screens), consider moving those off onto a replicated server (more than one if necessary).  More extremely, if you have the option of doing this, you could create a data mart specificually tuned for the reporting.  Obviously this might depend on how up to date the data has to be.It should be possible to do this without having to interfere in the application code, so it's not as an extreme approach as one might think.  If you need it to be up to date you could do something with change data capture at the expense of extra complexity.
If your DB server is I/O bound but you have plenty of spare CPU capacity (or maybe you can upgrade the CPUs) you might get some mileage from placing some or all of your database on SSDs.


Without looking into the technical specifics of your problem it's hard to see what can actually be done with the workload.