So I just got upgraded to Gigabit speeds today and in my excitement went and ran some speed test for fun

 (I understand speed tests don't directly reflect real world use)

To my surprise only 1 website I tried indicated gigabit speeds fast.com

Ookla speed test ,Shaws speed test and Google speed test all said between 500-600mbps.

I ran the tests back to back and only fast showed 1.3gbps. I do not really care if a speed test is off a bit. Just curious why they vary so much and if there is a more accurate way of doing the test?

I should add my PC is hard wired in with the whatever cable came in the box, probably 5e, and my PC lan port is 10/100/1000