Hello all , first post on this forum.
@ OP Firstly I recently bought an Asus 670 oc 2gb from OCuk ( terrific card btw ) Noticed some lag on the desktop, video, and gaming. ran msi afterburner, checked framerate in borderlands 2 and found I was being limited to 60 fps ( set ingame for unlimited framerate, no v-sync ). After checking event viewer and nvidia forums I found that the process NvStreamsvc (as seen in the task manager screenie you posted)
could be the cause . It was no effort to stop and disable the service then restart , I'm never going to use nvidia shield. that did the trick though! framerates increased in bl2 and better scores in heaven benchmark etc.
Also Ive been checking out rome 2 total war for purchase when bug free and found some details regarding the games graphics features
Quote from website 'In Rome2 we have a new custom Advanced Graphics Option checkbox: “Unlimited video memory”.
If you tick the box, the game will not downgrade your graphics settings, regardless of your available physical video memory.
If you then proceed and load a scene that requires more video memory than you have physically on your graphics card, the operating system may start swapping graphics resources to-from your system memory or hard drive' end quote.
This may or may not be relevant to your situation but hope the info helps.
Phew.... first post's are hard!