Optiplex 390 MT, video card upgrade to AMD Radeon HD 7470, slow performance

Agreed. You should have seen a performance bump. I would uninstall the Intel HD graphic driver. When done, restart and retest.

All radeon HD cards from 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000 are Legacy.  If you installed the latest 16.X Driver then it would not see the HD7470.  

AMD Radeon™ Software Support for Legacy Graphics Products

AMD Radeon™ R5 235X, Radeon™ R5 235, Radeon™ R5 230, Radeon™ R5 220, Radeon™​ HD 8470, Radeon™ HD 8350, Radeon™ HD 8000 (​D/G variants), Radeon™ HD 7000 Series (HD 7600 and below), Radeon™ HD 6000 Series, and Radeon™ HD 5000 Series Graphics products have been moved to a legacy support model and no additional driver releases are planned.

WHQL certified driver, the AMD Catalyst™ 15.7.1 driver will continue to be available for users running Windows® 10, Windows® 8.1, and Windows® 7.

http://support.amd.com/en-us/kb-articles/Pages/AMD-Radeon-7000-Series-Drivers.aspx

Thanks!

I went ahead and un-installed the AMD and Intel drivers using DDU tool while in the safe mode.  Then rebooted and had the drivers installed through the windows update. The startup time is now faster but not as fast as with integrated video.  

At the very start, the startup (after login) would finish within about 10-20 seconds, mostly loading anti-virus and similar tray apps.  After AMD install (installed Catalist software + drivers) + did windows update for AMD, the system would take good  1.5-2 minutes.  Now, after complete removal of the Intel and AMD  and re-install of AMD drivers through windows update it takes around 30-45 seconds.  

are there any other tweaks you recommend?

Thanks,

I recommend installing DOT NET 4.7 standalone as well as the Latest Catalyst 15.7.1  and CCC. DOTNET is required BEFORE AMD because CCC is a DOT NET Application.  Microsoft .NET Framework 4.7 (Offline Installer) for Windows 7 SP1, Windows 8.1, Windows 10 Anniversary Update, Windows Server 2008 R2 SP1, Windows Server 2012, Windows Server 2012 R2 and Windows Server 2016

https://www.microsoft.com/en-us/download/details.aspx?id=55167

Direct X June 2010 patch  download the file, extract into FOLDER,  Run DXSETUP.EXE as administrator.

https://www.microsoft.com/en-us/download/details.aspx?id=8109

Add Features Back to Windows media and Legacy Direct play,  DOTNET 2.0/3.5

Thanks,

.NET 4.7 is already installed on my computer.  

I see that I have directx 11 (using dxdiag)  and I am not too sure if I should install Direct X June 2010 patch (version 9 I believe).   Please advise.  

As far as turning the windows features on/off, I did not see Legacy Components.  My windows feature window shows no Legacy components.  

I found this driver:
http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=PCWM7

Should I install it as opposed to installing recommended AMD drivers?  Please advise.

Thanks,

I would test both our driver and the retail driver to see which gives the best results.

Hi, Chris:

Could you please clarify what you mean by

'test' and 'best result' in

- I would test both our driver and the retail driver to see which gives the best results.

What are the testing methods and what is the definition and metric that defines 'best' result?

Thanks,

Testing "performance" would be subjective to you and how you use the computer, what software is running etc.

Chris,

Could you please be a little bit more obvious:

1) What is 'your driver'

and

2) What is 'retail driver' ?

Could you please provide explicit URL links to the drivers you are mentioning...  

Thanks,