Unmodded - Eurogamer.
Modded at 1920x1080 resolution - Eurogamer.
Anti aliasing may be forced with the compatibility flag 0x004000C0. Sparse Grid Supersampling gives a blurry effect. Multisampling combined with transparency supersampling seems to work well (this author uses 4x on each). Some dark diagonal line artefacts are visible on my system occasionally with these settings but aren't obtrusive. DSfix's antialiasing should be turned off for this.
Ambient occlusion can supposedly be enabled with either 0x00000029 (Skyrim, soft AO) or 0x00000003 (Fallout 3, stronger AO effect). DSfix's AO should be turned off if you're forcing it here.
ProxyLib=C:\Program Files (x86)\Steam\steamapps\common\Dark Souls Prepare to Die Edition\DATA\res.dll
UseEndScene = false
Set processor affinity to only 2 of the available processors.
Disabling AMD Cool 'N Quiet in your BIOS can also fix the issue with low FPS.
Ensure Data Execution Prevention (DEP) is set to the default (Windows programs and services only).
RefreshRate = 60
Run as Administrator
Run this program in compatibility mode for:
Human Interface Devices
HID-compliant game controller
Useful if the automatic conversion fails. However, this will only transfer your game state WITHOUT your achievements.
The issue is that Steam is trying to install Gfwlivesetup.exe but Steam also stopped supplying the executable with new downloads.