so much wtf:
You probably have vsync on.
unless you want screen tearing, i suggest you keep it on (for most people anyways, unless you can maintain constant 60fps+), you guys are in the 1-3%... ie: nobody cares about your problems ;p
This is due to CDPR's decision to force double buffering in 1.0.7 in full screen mode (it was always the cause in borderless fullscreen mode)
A. no double-buffer means the system has to wait to render each scene before displaying it... you don't want that... horrible flicker and performance...
B. you do mean borderless windowed mode.
This caused Xbox One to go from 30fps to 20fps in CPU bottlenecked areas like Novigrad, and also the PC version now is locked at 40fps when framerate drops below 60fps refresh rate.
A. uh no, double-buffering implementations are not done via cpu these days... not since... 2003...
B. consoles just suck. ps4 has a 7870 ghz in it, pretty much... which is what i have in this pc... and if i dip to 25fps in some scenes (high settings), it means consoles will dip to 20 (not sure if they have a settings option, most console games don't)... which might explain it... they need to be running on low/medium to get 30 fps constant.
C. it doesn't lock fps at 40, that seems to be an SLI issue. currently, SLI is supposedly 'supported' but many users report no fps gain, or even loss. something with kepler gpus? no idea, i'd never buy nvidia...
is broken (fixed it for you).
game no longer scales with additional GPUs with any sort of vsync to prevent screen tearing
this just makes no sense, according to your previous statements:
single buffer: both fps above and below refresh will cause stuttering effect, since display has to wait for current buffer to be drawn. this is 1990s stuff...
double-buffer, fps above refresh no need for vsync. fps below refresh, tearing without vsync.
triple-buffering, introduces extra input+video lag, and is inferior to current double-buffered (page flipping) techniques (although, it may smooth out hiccups of 1 extra frame, at the mentioned cost). technically it's the same as the page flipped method (modern implementations anyways), shouldn't add lag, but it does for some reason... ask game devs why that is, no idea. maybe it's just not supported that well by gpus/drivers, and in that case triple-buffer implementation probably use the copy method.
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no, this is most likely due to your SLI setup... may want to search for some threads in that regard. some people have it working, others don't.
as for OP's 970... well, those have issues too... even in other games (i've browsed forums)... blame nvidia...
Deleting all config files to reset to default does nothing either, btw.
if you're using steam cloud, it will put them back. you have to turn cloud sync off, delete them, load game to create defaults, exit, then re-enable cloud sync.
save games are more of a problem, you have to clear steam's offline cache .vdf file, etc... or it will keep putting them back... honestly, steam cloud sync is annoying :\