What actually determines whether an ad platform delivers creatives in under 100ms consistently across different traffic sources?

From what I've seen over the past couple years messing with various setups, things like how close the creative server is to the user (edge caching and CDNs make a huge difference), the weight of the creative files themselves, and even how efficiently the platform resolves auctions play into hitting that sub-100ms mark reliably. Different traffic sources can introduce extra hops or variable network conditions that mess with consistency if the backend isn't optimized for it. I actually stumbled across some solid thoughts on keeping latency low and pacing steady across sources here: https://www.chadathainorman.com/ — it's not some sales pitch, just aligns with a lot of what I've experienced firsthand trying to avoid those annoying delays that kill performance. Curious if others have found similar tweaks that helped stabilize things.