It's been awhile since I played Arcanum but for what it's worth -
****Standard things to confirm*******
If running Win 7 / Vista - Did you ...
install as an administrator? (right-click the setup.exe and click "Run as an administrator" in the resulting dialog.
turn UAC off before installing? (see attached image) Set to "Never" notify or uncheck in Vista
install in a directory outside of Program Files?
right click the game shortcut, click Properties, click the Compatibility tab and check mark "Run this program as an administrator"?
try using different compatibility modes, starting with the newest and working back to the oldest?
install all mods as an administrator?
try re-running (as an admin) the HighRes.bat located in the Arcanum install directory . . . trying different resolutions. That failing, run the HighRes.bat (as an admin) and uninstall / reinstall the HighRes mod.
If you decide to reinstall the game make sure you uninstall it first and delete all files and directories under GOG.com\Arcanum before reinstalling. Also make a backup of your saves first. (see image)
*************
Make sure you DO NOT have the short cut set to run in window mode as I remember the game didn't like to be run in a window.
If you have a dual / quad core CPU, did you try setting the affinity to a single core? You can do it manually by starting the game, ALT-TAB out of the game, open task manager (CTRL - ALT - DEL ), find the [game name].exe on the Processes tab, right click the exe and click Set affinity . . . on the resulting dialog. Un-check all but the CPU 0 check box. (See attached image) Close the task manager and play the game. If this helps I suggest using
RunFirst as it sets the affinity for the game without having to go thru the task manager process each time you play.
Some users of Vista / Win 7 have limited the memory to solve some problems. I don't care for this method since it must be done before running the game every time and reset to the full memory after you stop playing. (see image) Make a note of the current setting prior to changing it since you will need to set it back after playing.
If you are running an AMD CPU you might try the
AMD Dual Core Optimizer Edit : No matter what I do, the post keeps naming two images affinity and two images Limit memor??? sorry.