Sounds like this will be a tough nut to crack...
A couple other things to try:
Windows 8.1 does some weird stuff with the mouse. It can slow down the input by trying to combine the movements for different programs. There is an update patch to help with this: http://support.microsoft.com/kb/2908279
Also, just turning off "Enhance pointer precision" in Windows mouse settings works for most prgrams, but many games call a function that enables it while in-game (Microsoft changed the way the function works). The MarkC fix sorts this out by applying an acceleration-less curve map to the enhance precision feature, so that's also worth a try. Make sure you select the correct DPI scaling and Windows version.
I'd keep it connected with DVI for testing these and see if there is any improvement.
Is there any particular hardware or software you changed around the time you began to notice this?
Well at that time I had just got the RAT3, thats when I started noticing the issue that my aim was badly off all of a sudden. Obviously back then I jumped onto the conclusion that it had to be the mouse.
I will run through what has changed (component wise) since then from previous version to new component maybe there is something wrong after I changed it all.
So my first PC build was actually premade, a standard desktop that I wanted to upgrade over time.
Components:
AMD A8-5500 APU with built in graphics ATI Radeon 7560D
4GB unbranded 1300Mhz RAM
Standard unbranded PSU maybe 300W
Unbranded Motherboard
Western Digital 1TB Green Caviar Drive
At the time I had a really cheap old monitor it might have even been a TV.
So back then I was really happy playing PC games, I had no problem with aim back then I forgot about sensitivity. This was because any sensitivity I chose even around 50% higher or lower than I should have had it at still felt good.
After I will I got into playing some bigger titles like Planetside 2, I was playing Black ops 2 a lot then as well; after I while I noticed that performance wasn't fantastic so i decided to buy a HD 6670 to get better fps.
So I installed the HD6670 with the drivers and I had better performance and I believe back then I believe I had everything still fine, this was on Windows 7 (guessing 64-bit).
I believe this was when I picked up the
RAT3 as my old mouse had some button problems, it was an old unbranded mouse guessing it was 125Hz but it did the job fine.
So again a while later I was happy but again I wanted more performance so I picked up my second
GPU (current) a HD 7850 2GB GDRR5 card.
Now at this point I may have had the problem occur when I had my old card, but I got the card anyway and after a short while I noticed my performance didn't really increase.
So I realized (still being new to PC gaming) that my CPU was bottlenecking, so I went and bought a
FX-8350 (current CPU) with an
Asus M5A78l-m/usb3 motherboard.
At this time I am sure that I purchased my
8GB RAM kit (current) G-SKILL 1600Mhz which did speed up the PC a lot.
So after those changed I have just bought mouse after mouse, I have added a HD Western Digital BLUE 1TB drive, I have changed motherboards (because 1 didn't support TDP of CPU).
So it could either be swapping out a component or maybe I changed a setting within Windows, but I have reinstalled my OS a couple of times fresh so I doubt it.
I have messaged a guy named R0ach to get his view on things, he knows quite a bit about latency etc. Hopefully he can give some input.
thanks very much for the support though, I hope I can crack it soon it's becoming more frustrating every day just wanting to play properly like everyone else can.