We run our website on a colocation rack in Amsterdam. We have several Windows 2019 servers on a load balance, very well optimized.
We have noticed that our TTFB reported by gtmetrix, webpagespeedtest and other similar tools, is very large. More specifically:
For page A via Cloudflare: TTFB: 966ms
For page A locally on the server: Waiting (TTFB): 27ms
For page B via CloudFlare: TTFB: 964ms
For page B locally on the server: TTFB: 177ms
For page C via CloudFlare: TTFB: 356ms
For page C locally on the server: TTFB: 145ms
and the list goes on. The difference in some cases is huge !
We are on the Professional plan on Cloudflare.
Any ideas ?