Internet Service Provider and Modem Configurations
What ISP Service do you have? Cable or DSL? Cable, I believe? I have optic fibre contract.
What ISP Modem Mfr. and model # do you have? No modem present in my house.
What ISP Modem service link speeds UP and Down do you have? Link> http://www.speedtest.net/my-result/5434896644
Cat6 cable I'm getting that either tomorrow, or this thursday. Current cable: Cat5e, should though perform good enough.
Factory resetted and turned everything possible off, including QOS (Disabled by default anyway), Traffic Shaping ((Disabled by default anyway) and I do not have IPv6.
Now I switched my firmware to DDRWT, slight increase of speed...sometimes

As stated in the main topic: I get 900+ Mbsp directly connected to ISP, through router is falls to 350~ ish Mbps. So it's either the router, or the cable, or both. Also having settings that would reduce the download speed by 70%, I find it bulls*** as a programmer, efficiency = NEGATIVE!
Gonna send this router soon enough to warranty, and hope to get a different one. Seems I'm not the only one fighting with this issue that has no clear solution to anyone.