Posted 27 July 2017 - 02:56 PM
Just some ideas here, but at my parent's house I discovered that internet speed tests over a certain point are also very CPU dependent, it's possible the older rigs don't have the single threaded performance to max speed tests.
Also many consumer routers that claim gigabit speed don't always maintain it or can't to multiple systems at once causing weird balancing issues. When ANY other thing on the network is using the internet for more than keep alive type pings it kill my speeds on the server over there by as much as 60% even though many times the other PC is only using ~200Mbps.
Here's a speedtest I just ran on my server with task manager CPU graph at the parent's house (The VM server with the 4930K @ 4.2Ghz) and it hits 22% CPU usage vs 1-2% before and after the test to get 800+ down (pretty much the max the router there lets me get, I can top 900 every time with a direct connection) and a low upload as my router there can't upload for shit the connection is actually 1000/1000.
Maybe that helps lead you somewhere, I know it was a frustrating mess until I figured out my scenario.
i7-5930K/GA-X99-UD4/32GB G.Skill/512GB Intel 600p/512GB Crucial M550/480GB ADATA SP550/5TB/GTX 1080 Ti/Rosewill Capstone 1000-M/Rosewill Blackhawk (main rig)
i7-4930K/GA-X79-UP4/32GB G.Skill & Team Vulcan Mixed/240GB Seagate 600 SSD/4 x 1TB/GeForce 315/Rosewill Capstone 750/Corsair Carbide 200R (VM Server)
i7-6820HK/Aorus X7 v6/16GB G.Skill/512GB Samsung SM951/1TB/GTX 1070/230w AC Adapter/94.24Wh Battery (Gaming/Fun Laptop)
i7-7500U/Razer Blade Stealth/16GB/512GB Samsung SM951/45w USB-C AC Adapter/53.6Wh Battery (Work Laptop)
i7-4770K/GA-Z87X-UD5H/16GB Kingston/240GB Seagate 600 SSD/2TB/GTX 1070/Rosewill Capstone 750-M/Rosewill Blackhawk (the wife took this one)
i5-3570K/GA-Z77X-UD5H/24GB ADATA/120GB Crucial M500 SSD/2 x 8TB/3 x 5TB/4TB/2TB/Antec BP550/Bookshelf (server)
i5-8600K/ASRock Z370 Gaming-ITX/ac/16GB Team Dark/512GB Sandisk 400 SSD/GTX 1070 Ti/EVGA Supernova 650 G1/Phanteks Evolv ITX (HTPC)