Thankfully, speed seems to be a strong point for PI. Below is a hand-picked compilation of speed-related suggestions from OSIsoft's feedback website. If you value your time as much as PI relies on time, please consider voting for some of these!
Root words of search terms that I used include: slow, fast, quick, speed, optimize, perform.
|PI DataLink||PI DataLink service for PI Server|
|PI Builder||Minimize the recalculation of volatile cells|
|PI System Explorer||Optimize SID resolution when viewing mappings in PI System Explorer|
|PI Data Archive||PI Data Archive: Improve piarchss performance|
|PI Vision||Improve display loading performance|
|PI Vision||Faster Login Experience on Mobile Devices|
|PI Vision||Trend Cursor - Slow Data Values|
|myOSIsoft||Make the Home page load faster|
|OSIsoft Learning||Reduce the load time of learning.osisoft.com|
Also, if you've been banging your head while using PI OLEDB Enterprise, I would highly recommend installing PI SQL DAS (RTQP Engine) on the PI Asset Framework server and using PI SQL Client instead of PI OLEDB Enterprise. PI SQL Client returns results much faster than I ever would have imagined was possible, even for large time ranges and multiple tags.