For many games it will be barely enough. Be very sure noting else is running. You likely can not use voice software but it all depends on the game. Games have gotten bigger over the years. Things like world of warcraft used to run on 56k dialup modems.
Some companies actually tell you what the minimum required connection is. If you know someone or have access to a faster internet connection you could test. While the game is running look in the network tab of the resource monitor. You can see the traffic going to the ip addresses of the game server. You may need to add together a couple of feeds to get the total rate. Be careful some of those numbers are in BYTES/sec and other in BITS.
I remember seeing some...