For help with PC settings for RealPanzer please look at the following:
1.Game runs best in WinXP or XP mode. Right click on the redorchestra.exe file and set it to run in WinXP mode.
2. Set your virtual memory to 4GB of Virtual Memory (not RAM) or more. Thidis space on your hard drive where the game writes a swap file. Most modern pcs have zero space allocated and the game absolutely needs this space.
3. Adjust the cache settings (CacheSizeMegs=32 ) in your darkesthour.ini file so that they match your graphic and sound card, typically values of 64, 128, 256, 512 or 1024 and higher. The standard setting is 32 which is a bit low for most modern PCs.
4. Download and use Large Address Aware Tool (LAA) on your redorchestra.exe file so that the game is able to use more than 2GB of RAM.
More detailed help at the Steamgroup site for DH_Realpanzer on the link below.