there are several factors you could be bottle necking your pc a few things to check
is the cpu at 100% (will cause a large amount of lag)
is hard drive completely full? (so will this)
run a bench mark test
check to see if your drivers are up to date(windows as well)
also depending on which 1050ti it is can differ performance
between:
zotac
asus
msi
if everything is fine try talking to the manufacture you might have a defective card?
First thing i would make sure to check is that you've put all of the wires in the correct connection spots
secondly i would switch your powersupply out if you have a spare one
Sorry that this is happening to you trust me i hate it when something isnt working right