I recently put together a new build with the following specs:
RAM: Corsiar Vengeance 8GB (CMZ8GX3M1A1600C10)
GPU: EVGA GTX 770
CPU: i7 4770k
I've noticed some severe keyboard lag (up to 30 seconds before response) both while gaming (Civ 5 and Sims 3 for the most part) and even without gaming if the computer has been up for a few days. From what I can tell, restarting fixes the issue temporarily so that is what I have been currently doing.
I initially thought the problem might be with the RAM, since the original set is not on the supported memory list along with the fact that restarting fixes the issue, so I swapped it out for the CMZ8GX3M1A1600C10 but the issue still persists. I've tried all the USB ports on the case and on the motherboard with multiple sets of both wired and wireless keyboard\mouse combos. Regardless of what I try to use, after about 1.5-2 hours of gaming I will start to see the lag in-game on the keyboard. If I exit the game, the lag does go away but I do see the lag outside of the game while the game is running. If I restart the computer, the lag goes away completely until I get another couple hours of gaming in.
I also thought this might be GPU issue, because this issue was originally only being seen while in-game, but I did not play any games for a couple days and started noticing the lag during regular use as well. Besides, I do not think the GPU should be interfering with the processing of the keystrokes but I'm open to anything at this point.
I'm still in the process of troubleshooting but I have not been able to find any fixes by Googling the issue. I've reached out to Gigabyte but I would love to be able to fix the issue without having to send it in. Any help is appreciated.