I am bit hurry while typing down this story. Let's cut it short, for last 3 days I found that JIO's downlink is quite slow, and very much slow whenever I go indoor and Jio LTE moves to LTE1800 or LTE850.
Using the Jio's Netvelocity app, I checked out all three LTE frequencies - Band 40/Band 3/Band 5
Location : Barrackpore
Time : 00:00 to 01:00 am, 2016-09-24
N.B. These speedtests do not always represent real time downlink or uplink.
LTE-TD on 20MHz of 2300MHz [Band 40]
LTE-FDD on 5MHz of 1800MHz [Band 3]
LTE-FDD on 5MHz of 850MHz [Band 5]
** However RCom is also offering LTE over Band 5 and they are sharing the spectrum with R-JIO. And RCom's 4G speed is more than that.
If you don't believe these Netvelocity results, let me share a screenshot while I was upgrading my Opera Desktop Browser. See the speed and decide.