It's unlikely that the # of processes are causing latency, the reason being is that they are multi-threaded, and as long as you have good horsepower on your server that's running your vizzes (i.e. clock speed, # of cores, memory, disk I/O speed), then this shouldn't be a factor. You can view minimum specs here: All Technical Specifications | Tableau Software
How long is performance taking? Maybe the workbooks need to be tuned, you can see this as a start on best practices.Best Practices for Effective Dashboards
Also, run a performance recording to see if there's a possible bottleneck. Create a Performance Recording
Please refer --->6 Tips to Increase Dashboard Performance
I have created a Video on Performance recording
Way to analyse and improve the backend queries.