i take a look through the game file.
like perfomance.xml
=
<?xml version="1.0" encoding="US-ASCII"?>
<performance>
<!--Tahiti XT [Radeon HD 7970/8970 OEM / R9 280X]-->
<device vid="1002" did="6798" preset="2" />
<!--Curacao XT [Radeon R9 270X]-->
<device vid="1002" did="6810" preset="2" />
<!--Tonga PRO [Radeon R9 285]-->
<device vid="1002" did="6939" preset="2" />
<!--GF110 [GeForce GTX 560 Ti]-->
<device vid="0x10DE" did="0x1082" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 560 Ti]-->
<device vid="0x10DE" did="0x1087" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 560]-->
<device vid="0x10DE" did="0x1084" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 570]-->
<device vid="0x10DE" did="0x1081" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 570]-->
<device vid="0x10DE" did="0x1086" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 580]-->
<device vid="0x10DE" did="0x1080" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 580]-->
<device vid="0x10DE" did="0x1089" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 580]-->
<device vid="0x10DE" did="0x108b" preset="0" fpslimit="30" />
<!--GF110 [GeForce GTX 590]-->
<device vid="0x10DE" did="0x1088" preset="0" fpslimit="30" />
<!--GK104 [GeForce GTX 660]-->
<device vid="0x10DE" did="0x1185" preset="0" fpslimit="30" />
<!--GK104 [GeForce GTX 670]-->
<device vid="0x10DE" did="0x1189" preset="1" fpslimit="30" />
<!--GK104 [GeForce GTX 760]-->
<device vid="0x10DE" did="0x1187" preset="1" fpslimit="30" />
<!--GK110 [GeForce GTX 780]-->
<device vid="0x10DE" did="0x1004" preset="2" fpslimit="30" />
<!--GK110 [GeForce GTX Titan LE]-->
<device vid="0x10DE" did="0x1003" preset="3" />
<!--GK110 [GeForce GTX Titan]-->
<device vid="0x10DE" did="0x1005" preset="3" />
<!--Geforce GTX 780 Ti-->
<device vid="0x10DE" did="0x100a" preset="2" />
<!--GeForce GTX 980-->
<device vid="0x10DE" did="0x13c0" preset="3" />
</performance>


Configure Graphic & Language - Documents\The Witcher 3

File : user.settings

[Gameplay/EntityPool]
SpawnedLimit=150
[Hidden]
HasSetup=true
uiVerticalFrameScale=1
uiHorizontalFrameScale=1
[Localization]
SpeechLanguage=DE
TextLanguage=DE
[Viewport]
VSync=true
Resolution="2560x1080"
FullScreenMode=2
VSyncThreshold=0
OutputMonitor=-1
[Budget]
cvMaxAllowedLightsShadowTime=1
cvMaxAllowedApexDestroTickedTime=0.2
cvMaxAllowedGrass=30000
cvMaxAllowedDecalsDynamic=10
cvMaxAllowedDynMeshes=104857600
cvMaxAllowedChunksSkinnedTime=2.5
cvMaxAllowedTrianglesSkinned=100000
cvMaxAllowedDecalsSSTime=0.1
cvMaxAllowedLightsShadow=3
TerrainTileMipDataBudget=100
cvMaxAllowedApexTicked=60
cvMaxAllowedActiveEnvProbesTime=0.1
cvMaxAllowedStatTextures=314572800
cvMaxAllowedSpeedTree=5000
cvMaxAllowedLightsNonShadowsTime=0.2
cvMaxAllowedSpeedTreeTime=2.2
cvMaxAllowedChunksStatic=1500
cvMaxAllowedTrianglesStatic=500000
cvMaxAllowedHiresChunks=25
cvMaxAllowedDecalsDynamicTime=0.5
cvMaxAllowedLightsNonShadows=40
cvMaxAllowedChunksStaticTime=1.5
cvMaxAllowedChunksSkinned=400
cvMaxAllowedApexDestroTicked=20
cvMaxAllowedStatMeshes=209715200
TerrainTileMinTimeout=2
cvMaxAllowedHiresChunksTime=0.2
cvMaxAllowedApexTickedTime=0.5
cvMaxAllowedCharTextures=209715200
cvMaxAllowedParticlesCountTime=0.2
cvMaxAllowedParticlesCount=1000
cvMaxAllowedGrassTime=1.5
TerrainTileTimeout=10
OcclusionQueryAdditionalMemory=5
TerrainTileLoadingTimeout=5
cvMaxAllowedDecalsSS=160
[Audio]
Subtitles=true
[LoadingScreen/TCR]
ShowProgress=true
[Game]
DoNotPauseWhileStopped=false
[PostProcess]
MotionBlurPositionTreshold=0.05
MotionBlurRotationTreshold=1
SSAOSolution=2
[Input]
PadVibrationEnabled=true
KeyboardCooldownSpeed=0.1
InvertCameraXOnMouse=false
InvertCameraYOnMouse=false
CameraAutoRotX=true
InvertCameraX=false
UIMouseSensitivity=1
CameraAutoRotY=true
RightStickCameraSensitivity=1
InvertCameraY=false
RightStickAimSensitivity=1
MouseSensitivity=1
[Gameplay]
Difficulty=2
[LevelOfDetail]
SwarmHideDistance=200
DecalsHideDistance=80
DimmerHideDistance=60
DynamicDecalsHideDistance=20
StripeHideDistance=60
[General]
ConfigVersion=1
[LoadingScreen/Editor]
Disabled=false
[LoadingOverlay/TCR]
FadeOutCooldownExtraTime=1
FadeInSpinnerTime=1
NoninteractiveSpinnerTime=3
FadeOutSpinnerTime=1
NoninteractiveEndCooldown=1
[Visuals]
InventoryBgColorScaleB=0.036
InventoryFixedLuminance=0.25
InventoryBgColorScaleG=0.034
MovieFramerate=30
GammaValue=1
InventoryBgColorScaleR=0.02
[Rendering]
GrassDensity=2400
DecalsSpawnDistanceCutoff=10
TextureStreamingHeadsDistanceLimit=10
GlobalOceanTesselationFactor=64
TextureStreamingCharacterDistanceLimit=50
CascadeShadowFadeTreshold=1
CascadeShadowDistanceScale2=1.5
TextureStreamingDistanceLimit=40000
TextureMemoryBudget=800
CascadeShadowDistanceScale3=1.5
MeshLODDistanceScale=1
ScaleformTextureUnstreamDelay=2.5
DecalsChance=1
TerrainReadAheadDistance=200
HairWorksLevel=2
TerrainScreenSpaceErrorThreshold=1.6
MaxTerrainShadowAtlasCount=4
TextureInFlightCountBudget=12
TerrainErrorMetricMultiplier=6
CascadeShadowmapSize=3072
CascadeShadowDistanceScale0=1
MeshRenderingDistanceScale=1
CascadeShadowQuality=1
CascadeShadowDistanceScale1=1
[Input/Gestures]
EnableSwipe=true
EnablePan=true
EnableGestures=true
EnablePinch=true
[LoadingScreen]
FadeInTime=3
SkipShowWithAnyKey=true
GameRevealTime=3
SkipHideDelay=3
SkipInputDelay=0.25
FadeOutTime=1.5
SkipAutoshow=false
[Engine]
LimitFPS=30
[Rendering/SpeedTree]
GrassGenerationEfficiency=0.075
GrassDistanceScale=1.5
FoliageDistanceScale=1.8
FoliageShadowDistanceScale=54
GrassRingSize=16777216
[Save]
ShowCompatWarning=true
[Kinect]
Kinect=true
[Foliage]
MaxVisibilityDepth=24

Hi i'm new here :)
There isn't the gtx770....can i put in this list or my gpu it's going to explode ;) ?