SG Broadband Community

Hi, I've recently been upgraded to a 1 gigabyte broadband connection. We have two PCs connected by LAN. One of them achieves 800 Mbps download and 100 Mbps upload, which is within the ISP parameters, while my Lenovo T450s laptop only achieves 100-450 Mbps download and 100 Mbps upload. I've tried different cables (both Cat 5e) to no avail. TCP Optimiser does not improve performance, in fact it slows it down.
I discovered that if I pause Kaspersky protection I get download speeds of 850 Mbps.
Any tips please?
Thanks!

I'd just turn off any real-time "web" protection" in your anti-virus.. You can also just rely on the Microsoft Essentials anti-virus that's built into Windows.