gtx 1050 ti cuda compute capability 2.1?

i an on ubuntu 10.04. A cheap gtx 1050 ti from China.
i can only install driver version 390. higher versions fail.
i, therefore, installed cuda 9.1
does not seem able to run cudnn.
the device query gives

Device 0: “GeForce GTX 1050 Ti”
CUDA Driver Version / Runtime Version 9.1 / 9.1
CUDA Capability Major/Minor version number: 2.1

~/cudnn_samples_v7/mnistCUDNN$ mnistCUDNN
CUDNN failure

do i just ditch this card and get some other manufacturer? if so how do i know new will work?

Ubuntu 10.04 is not supported. Try again on an Ubuntu version shown in the above link.

Compute capability 2.1 is not correct for a GTX 1050 Ti.

Based on the information here, it appears to be a counterfeit device.

sorry ubuntu 18.04

It is also not supported by CUDA 9.1.
And it could be they sent you something from 2009.