Now, the reason why I am particularly annoyed is because AC2, on the other hand, runs like butter. Honestly, it doesn't lag AT ALL. I would suppose that there are only minor graphical enhancements implemented in ACB (as far as i've seen), so the performace shouldn't drop dramatically. But it does. Lowering the resolution and the graphics settings helps a bit, but the game still lags.
Honestly, this is a pretty powerful laptop and the game shouldn't lag on it, in my opinion. In my mind, this point to bad PC optimisation.
In the mean time, I reduced some of the graphics options by 2 levels and the game runs acceptably smooth now. However, in my opinion, I shouldn't have to reduce the graphics options this much, if at all, for the game to run ok, again having in mind how AC2 runs on my PC.
As a side note, have you tried running/playing the game On 2 CPU cores, or even 1 core (depending on your processor i.e. Quad CPU) ? Not sure if this can solve your problem, but there is no harm in trying it.
After you have loaded the Game's Main Menu, Open Task Manager (CTRL+ALT+DEL/CTRL+SHIFT+ESC) and Click on the Processes Tab. On the Processes tab, at the bottom click on the 'Show processes from all users' Button. Now Right click the process i.e. ACBSP.exe, and Click on the 'Set Affinity' option, and then 'Uncheck' any 2 boxes labelled as CPU 0, CPU 1 etc., and click on the OK button. But first Launch the game and then press 'ALT-TAB' to go back to the desktop, and now open the Task Manager, and follow the above method. Press 'ALT-TAB' to go back to the game.
Just make sure to run the process i.e. ACBSP.exe, with any 2 cores of the CPU. Or Uncheck any 3 boxes, to play the game on a Single CPU core. Btw, does the game fully utilize all the CPU cores ??
Another method: Insert the following command inside the Target line at the game's Shortcut TAB. Make a Shortcut of the game's .EXE and insert the following command (Right-click---->Go to properties---->Shortcut TAB):
As a side note, also try launching the game under 'Windows XP SP2 Compatibility Mode', and see if this makes any in-game difference or not ? This can be easily done under Windows 7/Vista. Btw, which OS are you using ?
The above low FPS/lag could also be a GPU driver issue. Maybe Nvidia and ATI may release a BETA version of drivers for ACB. Try to close every other Background process while gaming.
Ok, so at the highest settings (inluding 1080p resolution), the game runs at about 14-15 FPS with relatively low action
When I decrese the settings by 2, it starts running at 23 fps with low action and environment in the background and abotu 19 with high action and/or environment (i.e. city panorama in the background as opposed to a street).