Dell optiplex 790 gaming build issues ! Help required :(

[humzayunas]

Hi guys I'm from multan
Hi guys i built my pc for gaming. I got Master cooler PSU of 550 watt and with 2 8 pin or 6 pin connectors . I've inserted new sapphire 7870 ghz edition card properly in my MOBO. But i'm getting weird hitches on the screen mostly times i got error that amd driver stopped responding and recovered successfully and mostly games won't play and i see various dost and fins on screen but when i reduce refresh rate and keep system idle then after some time it becomes stable ....... I'm not getting that what's the issue . Mostly i felt that these dots things happen and display driver stop working but after that i tried each and every thing i can but not able to realize that what's the real issue . Kindly help me regarding this . I updated drivers and every thing i can do from my end i did . what i should do now ? is my MB compatible with card or any other issue ? What i should do ?
One more thing that i also tried to play gta v and that was fine and fps then i got no crash nothing and played for long time but when loading and etc like that i get hitches on screen and many thing mostly game crashed but once it starts it works fine and then i tried to play assassin's creed syndicate but during loading it gets crashed at various points that's the issue . I'm not getting any solution i tried.

 

[Deadp00l]

The problem you are experiencing could be from many things but you must check and rule out one thing at a time, the error amd driver's has stopped working could be due to software conflict or corrupt files from when you first installed the drivers, use a program like driver sweeper to completely remove the drivers and all its files it will also clean the registry reinstall the drivers then check if the problem persists oh and yeah if you had nvidia gpu installed before you need to use driver sweeper to remove those as well, as for the hardware side could be many things from temps to voltage to insufficient power from the psu or a faulty gpu use a program like msi afterburner to check temps, volts, usage of the card also check that the 6 pin connectors are properly inserted in the card.

 

[CyCo]

pretty much what Deadp00l suggested, make sure your card is seated well and those 6/8pin power connectors are a proper fit, take em out clean em if needed insert em well and double check the pins aint lose from inside
when done boot up to Bios and disable built in graphic card (funny it may sound), and follow deadp00l's steps by running driver sweeper and so on
hopefully its nothing more than corrupted/overlapping drivers from your previous installs, if the problem remains, see if you can get hold of another PSU to check your system with.