I don't do reviews often, but I want to help my geek friends save days of research and frustration that I went through to finally get the absolute most speed out of my Gigabit internet. There are some golden nuggets here that you need to know.
When I first upgraded to the new gigabit here in Denver (from Xfinity), it was using their new Cable Modem/Router device (XB6-A), and I was only getting 500 Mbps download speed. It was also lagging in our house when several people were gaming, and others were downloading, or even accessing intensive web-pages. (lagging = pings were going up).
Since upgrading to this Netgear CM1000, upgrading my cabling, and factory resetting my router, I'm now getting the most download throughput (~941 Mbps) and the lowest pings I've EVER seen! The connection is rock solid throughout the house.
SHORT ANSWER: Get this Netgear CM, upgrade your ethernet cables to Cat 6 (or Cat 5E for short distances) and then Factory Reset your router to get the most speed. You still may need a new router to reach gigabit speeds. I'm getting the most download throughput (~941 Mbps) and the lowest pings I've EVER seen!
I did lots of tests comparing this cable modem to the XB6-A that Xfinity provided. Here are some big things I learned:
1) Make sure your ethernet cables going from the cable modem to the router and from the router to your PC are CAT6 or at least CAT5E (for short distances).
2) Upgrading to this Netgear CM1000 Cable Modem LOWERED my ping/latency compared to the XB6-A that Xfinity provided. I just got a 5 MS Ping to the google server here in Denver! UNHEARD OF. Most of the time it's around 8-9ms with this new cable modem. I was getting 11-14 w/ the Xfinity modem. If you're a gamer, a lower ping matters!
3) The Xfinity XB6-A modem/router combo doesn't work too well when you have your own router also connected to it. Xfinity recommends you only use their device and disconnect your router.
4) Around 941 Mbps is the max download speed that modern gigabit routers/switches can do right now so don't be worried if you can't get above that.
5) Many routers can't handle gigabit download speeds, especially if you've enabled any of the features like QoS, Traffic Meter, Keyword block, etc. My Netgear Nighthawk (R7000) was only getting 400-500 Mbps (using speedtest) because I had enabled some of these features. Even when I disabled these features, the speed was still low. Doing a FACTORY reset fixed it, and now I'm getting 937 - 943 Mbps download speed!!!
The reason these routers slow down when you enable extra features is that it disables CTF (cut through forwarding) and the router no longer uses it's faster processor. Some of the newer routers can still maintain max download speeds of 941 Mbps while also allowing you to use QoS and other features.
6) There's a great website called Small Net Builder that compared routers to see which could reach 941 Mbps download speed. I recommend you check that out if you need a new router.
Keep in mind that this Netgear CM1000 is JUST a cable modem. It's not a router. So if you only have one device you want to wire into it, you're fine, but if you're going to have more devices, and wireless, then you'll need a router too.
The Xfinity provided XB6-A is both a cable modem and a wireless router in one. I think it has some flaws that need to be worked out but appears to be a beefy piece of hardware. You can save yourself the $10/month rental by getting this Netgear CM1000.
P.S. I do plan to upgrade my router so that I can still get 941 Mbps download speed while enabling QoS. With QoS, it will set aside a portion of your bandwidth (say 20%) for high priority traffic like gaming that needs low latency, and then it will limit all other connections (like large downloads) to the other 80% the connection. Keep in mind; if you enable this and run a speed test, it will appear lower just because it's now reserving part of your bandwidth for other devices/traffic in your home.