By default, EIGRP will automatically load-balance across equal-metric routes (four by default, six maximum). EIGRP also supports load-balancing across routes with an unequal metric. We must use the variance command to tell EIGRP to load-balance across unequal-metric links
Router(config)# router eigrp 100
Router(config-router)# variance 2
Router(config-router)# maximum-paths 6
The variance command assigns a “multiplier,” in this instance of 2. We multiply this variance value by the metric of our Feasible Distance.Thus, any Feasible Successors with a metric within twice that of our Feasible Distance will now be used for load balancing by EIGRP.
Remember, only Feasible Successors can be used for load balancing.The maximum-paths command adjusts the number of links EIGRP can load-balance across.
Click here for EIGRP MAXIMUM PATH AND VARIANCE Lab with GNS3