Selenium performance with .NET and Jenkins - How to profile and improve it?

The fact that it is a VM should not be a problem, and RAM sounds like it is good. What OS is being run though? Some of the Windows OS have significant speed differences between the different bit versions (because of demands on hardware). This is especially noticeable in Vista but I have noticed a difference between Windows 7 and Server 2003.

I have found that there is a huge problem if the machine running the 64bit VM is a 32bit machine. It often seems to work well for a while and then as it continues to run tests will slow down. Which should be a duh but the main thing is that there may be too many VMs being run from the same place. Other programs will be affected by this and that can help troubleshoot if your VMs are on a company farm.

The other factor that has made a significant difference is if you are running the tests against different browsers. IE8 and IE9 will take the same selenium command and run them at different speeds. I don't know why this is, I just know that I have seen it. Make sure the staging machine has the current version of Chrome (or at least the same as your dev machine).

How the staging machine is networked to the database might be making a difference. This seems like a very small chance but if there is firewall crap between the two VMs that can have significant impact on time.

The only other thing I can think of that might be changing the length of time is if there are other programs being executed on the on the staging machine at the same time. Checking the CPU usage might helpful. Personally, I have noticed that my VM uses a lot more of the CPU than my personal machine. If this is the case the only solution I have found so far is to give the VM more processing power or to only run the test and nothing else.

Good luck!