Registry changes impacts Resolution in game?

Hello, 
I run Flight Simulation 2002 on a P4 2,4 Mh; 1 gig memory, GF4 TI 4600, XP Pro SP1 with 2 screens on the video card , I run 1280x1024x32 resolution. I did change 3 keys in the registry :
Hkey local machine\system\current control set\control\session manager\memory management
to improve the performances of the PC.
1/ Second level cache from 0 to 512 (to use all the L2)
2/ Large system cache from 0 to 1
3/ Disable paging executive from 0 to 1
and as result FS2002 can only run to a maximum resolution of 1024x768x32
, the game does not allow any higher resolution ?? the PC is still running at 1280x1024x32 all the other applications are running at 1280x1024x32 ...(of course I did remove the changes and all is OK for FS2002)
BUT who can explain why these changes impact the resolution available at game level and only at game level
Thanks in advance
Emile
EBBR

I run Flight Simulation 2002 on a P4 2,4 Mh; 1 gig memory, GF4 TI 4600, XP Pro SP1 with 2 screens on the video card , I run 1280x1024x32 resolution. I did change 3 keys in the registry :
Hkey local machine\system\current control set\control\session manager\memory management
to improve the performances of the PC.
1/ Second level cache from 0 to 512 (to use all the L2)
2/ Large system cache from 0 to 1
3/ Disable paging executive from 0 to 1
and as result FS2002 can only run to a maximum resolution of 1024x768x32

BUT who can explain why these changes impact the resolution available at game level and only at game level

Thanks in advance
Emile
EBBR