Why don't you try asking CYRI for help?
or
If that GPU supports GeForce Experience, maybe it has a ONE CLICK OPTIMIZATION feature?
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You can go to the official The Witcher 3 Wild Hunt site and look for it's system requirements..
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Try installing a game booster/optimization software then run the game from there. You might get lucky..
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If all else fails, if you have a copy of the game, try running it on the lowest settings working your way up.. You know, there's a mod where you can tweak the graphics config of the game.. Look for it in the Nexus Mods site.. Again, start at the lowest settings working your way up..
You know, sometimes, even if you don't fall under the category of the minimum system requirements, you might just be able to run the game. So, try EVERYTHING. A true gamer does everything to be able to run every kind of game.. Specially, The Witcher 3: Wild Hunt. Luckily, I don't have to try all these 'cause I have a GTX 970. LOL!