My boards are starting to experience significant delays at busy times of day - I'm wondering if there are any 'rule of thumb' performance considerations / enhancements / resolutions / ...

(Dedicated server - windows - and I have 25+ years in the software industry.. I am fairly comfortable with this stuff)

A couple of years ago I recall 5000 being suggested as a limit for a post count total in any forum - but I see so many forums exceed that... and I do too in most of my forums.. What sort of impact / hit are the long forums? Threads?
(I mean - I/O? CPU? Memory? locking bottlenecks? ?)

I limit threads to 200 posts.. Is this reasonable? I'm thinking the CPU for long threads was an issue?

I know the 'recent visitors' is a hit on system resources (I saw that when I implemented it
'back when' - how much - my visitors like to see this, but faster response would be better too.

I recall reading the I/O locking mechanism was the real longer term bottleneck for forum performance as activity grows - I'm not at the 3,000,000 + pages a month number (yet), but ??

My forums continue to grow - 2-3GB a day bandwidth right now, 10-20% growth a month.

Last fall I watched another large BB (similar in size and activity to mine) upgrade to Threads, and it has been a spectacular disaster for them. I do not see any upgrade path for me? (I can not afford the outages or the problems they had - I have nearly 30 paying sponsors)

Thanks for any suggestions here..

Bob