RX 460 driver troubles

[silverjay928]

Hello guys I have an RX 460 2gbthat requires no pcie power that I put in a DELL OptiPlex 380 motherboard that has a core 2 E7500 with 4gb ram 250gb hard drive and I have it all connected to an ANTEC 500w 80 plus so no power issues all coolers are working everything is slotted in correctly and all power connectors for the board all drivers and I still cant get my GPU to work at full performance it wont even play YouTube videos at 720p let alone play Roblox at all. I have updated to the driver  18.10.2 and a 18.5 version and if I try a 17.8 version it will give me a code 1603 cant finish. is the motherboard in compatible? ( DELL e93839 az0422)  I have been at this for 24 hours now can someone help or send me to another forum for answers? again the gpu does display image but will not perform at all and is struggling to do even the most basic video tasks I reinstalled win 10 and will be reinstalling the drivers but I doubt that will help. again anything will be of help ive tried DISM image clean up  and SFC scan in CMD as well

[Reznik]

I don't see any Windows 10 support or drivers for OptiPlex 380 on Dell's site.  Maybe a driver it's using for something else is causing issues.   

[silverjay928]

6 hours ago, Reznik said:

I don't see any Windows 10 support or drivers for OptiPlex 380 on Dell's site.  Maybe a driver it's using for something else is causing issues.   

I was thinking something like that or the pcie slot power limit being too low the card is supposed to be a 75w tdp and a lot of reading but nothing I could find on this specific motherboard but a lot about OEM board saying they only have a 25 watt TDP which is enough to run the card on display mode but nothing more