4G is a fourth generation of the mobile broadband network while LTE is a long-term- evolution of the fourth generation network.

Additionally, 4G which is often referred to as 3.9G is a kind of system that replaced the predecessor 3G by offering more great and significant speeds while the 4G LTE is an improvement of 4G that renders faster connections than both the 3G and 4G.

In the advanced 10th version of networks, 4G LTE is capable of reaching a decent speed of 1Gb/s while its counterpart 4G reaches a peak speed of 100Mb/s. Therefore the LTE offers a faster and reliable connection than 4G and is thus faster.

Credit: Quora