Since this issue is intermittent, I was not able to get any screencaptures showing whats going on until now. First Screenshot shows that some assets that MISSED on cache took very long time to load.
You can see a 2mb file took almost 3 minutes to download, yet a 5mb file that CF has cached was downloaded in 579ms. The next screen shot is the same assets but I refreshed the page, so CF has cached them.
You see it finished all assets in under 1s now that CF has them cached.
Here is another test I did with CURL… I ran it about 10 times… it downloaded the asset every time in under 3 seconds, except once it took 35 minutes. The very last call I show is to the origin, just to show its not the source of slowness.
Any ideas why some things are intermittently slow when cache-status MISS?