I've written recently about my limited satisfaction with my new laptop, an MSI GT70.
Another problem I discovered recently was that download speeds were limited to 1.5 Mbps. Since this slow rate persisted regardless of whether I tried the wireless or Ethernet connection, I thought the blame was with my ISP; but after extensive testing, it turned out that other laptops were able to get better speeds, up to 15 Mbps, through the very same connection. It was only my MSI laptop that was seeing very low download speeds. Interestingly, upload speeds appeared to be unaffected, and the download speeds were also fine when using USB tethering through my smart phone, which used the same internet connection, but bypassed the Killer network cards.
Eventually, it turned out that I needed to install a driver update for the Killer network cards (both wireless and Ethernet) that come with the MSI laptop. I was able to download new drivers here. After removing the old drivers and installing new ones, I'm now seeing download speeds I expected to see.