Random system Freezes on two different machines in the same room

I am at my wits end and looking for suggestions. I have been encountering a problem with 2 desktop workstations in my home office. This problem began on an old dell machine, and when I finally gave up diagnosing it, I purchased a new desktop, only to have the problem follow. (Machine specs below).

The problem is that both machines will simply stop responding. No mouse or keyboard input, can't switch to another tty, nothing. The only way to get the machine back is to power cycle. When I bring it back there are no errors in xorg logs, nor in the systemd journal, the logging simply stops at the point of the freeze. This can happen when idle, or under load. It happens between 2 and 12 hours after the machine is booted.The machine is also not reachable via ssh. I don't have detailed specs on the old machine, it was a freebie I picked up from someone. It was a core2duo with 2GB of RAM running Fedora 21 The new machine is a 4th gen i5, 32GB of RAM, Nvidia Geforce GT 720 using the nouveau driver. When I first got it I installed Fedora 21, when I thought the OS may be the issue I installed Arch.

My troubleshooting steps thus far:

• I have replaced the computer


• Changed Distros from Fedora to Arch


• I thought this may be a power related issue, like a drop in the outlet voltage so I tried different outlets in the same room, and eventually put the machine on a new UPS to try and eliminate the house power and the power strip as an issue


• I'm desperate so I just switched out the mouse, if it happens again the keyboard is next.

At this point the only things that are the same are the location, the modem and router, the monitor and the network cable. Im starting to run out of ideas, any help would be much appreciated.