Yes, I have one other wired connection and two laptops, but I doubt it's a congestion problem since my issue(s) occured when only one computer was being used.
I have not isolated the VOIP with a static ip nor do I know how to do that. However, my packetloss is not just apparent in VOIP. Additionally, I often have high ping in online games, packetloss while pinging websites, and overall internet connection is slow.
What exactly changes once I turn off DNS relay?
You probably won't need to make any configuration changes after disabling DNS relay. All this setting does, is allows you to use your router IP as a DNS address. For example, if DNS relay is on, the devices currently connected to the router will have their DNS resolution addresses set to the router's IP. If this setting is turned off, the DNS servers from your ISP will be given directly to any device connected to the router. This only affects DNS and not your actual IP addresses. Quite a few people report no issues with their routers after disabling DNS relay, so this would be a good first step.
For further troubleshooting, you may want to connect one of your computers directly to your modem... check your ping times in games and through the command prompt to various sites with this setup. There is a very good possibility that you have some type of line issue, or there is an internal ISP issue that is causing your problem. This obviously will rule out any problem with the router.
If the router is indeed the culprit, and you still have these problems after disabling DNS relay, if it's possible you may want to change the wireless settings on the router to support wireless G or N only (not a mixed mode). Let us know how this works out for you.