When you get into creating workflows for your SharePoint Server 2010 farm, you may run into some delays or errors.  The one most commonly seen is...

Due to heavy load, the latest workflow operation has been queued. It will attempt to resume at a later time

This is because SharePoint has a default limit of 15 workflows that can run at the same time.  If you didn't know, there are quite a few workflows that run in the background all the time.

There are 2 main settings that you should be concerned with.  The first is the WorkflowPostponeThreshold which controls how many workflows can execute at a time.  The default is 15 and you can run this command in the SharePoint 2010 Management console to see what your setting is...

Get-SPFarmConfig | Select WorkflowPostponeThreshold

To change this setting, modify the number in the following statement to fit your needs and run in the same console...

Set-SPFarmConfig -WorkflowPostponeThreshold 75

The other setting is the WorkflowBatchSize which controls how many workflows can be in the 'queue' at a time.    The queue is basically a 'bucket' of workflows that are waiting for the timer service to execute them.  To see what your setting is, run the following command in the SharePoint 2010 Management console...

Get-SPFarmConfig | Select WorkflowBatchSize

To change this setting, modify the number in the following statement to fit your needs and run in the same console...

Set-SPFarmConfig -WorkflowBatchSize 200

This works for 3rd party workflows, like Nintex too!  Be sure to monitor your servers and their performance to make sure you aren't overwhelming your environment.