Why is Safari's Wi-Fi speed significantly lower than Opera's on the same network?

i have been having this problem for 1 week , where safari gets 0.5 mbps internet speed and only a few times it reaches 100 mbps . Today i did a speed test with opera browser and safari ......and this was the result . 2 different browsers connected to same wifi and same speed test and at the same time but i get 2 different speed results . I DONT LIKE OPERA , I JUST WANT TO USE SAFARI CAN ANYONE TELL ME A SOLUTION FOR THIS

[Re-Titled by Moderator]