Guys I've been searching for my bottleneck and I think I've found it. Before this I changed my ethernet adapter to a USB-C one and switched all cables to CAT 7 but the speed difference was marginal.
My bottleneck was
Kaspersky. Was using Kaspersky Internet Security 2019 before this and my speed averaged around 650-700Mbps download. Switched to Bitdefender Total Security 2019 and these are my results:
Bitdefender enabled with Bitdefender FirewallSpeedtest: 818Mbps down 496Mbps up
Fast: 1.1Gbps down 480Mbps up
Bitdefender enabled with Windows FirewallSpeedtest: 806Mbps down 495Mbps up
Fast: 1.2Gbps down 470Mbps up
Bitdefender enabled with no firewallSpeedtest: 804Mbps down 500Mbps up
Fast: 1.1Gbps down 500Mbps up
Bitdefender disabled with no firewallSpeedtest: 786Mbps down 499Mbps up
Fast: 1.1Gbps down 460Mbps up
Note: All Speedtest tests were using TIME Shah Alam server
Your results may vary, if you see the previous pages I posted my iperf results and the max transfer speed I got was around 900Mbps so getting 818Mbps download is alright for now. So if you're using Kaspersky and experiencing slow speeds then can give Bitdefender a shot, let me know if it works/doesn't work for you