So my desktop is set to 640X480 @ 60 in ArcadeOSD. Adjusting the porch values doesn't really do much in terms of moving the image. If i pick a 15k res like 384 X 240, adjusting the porch values moves the screen a lot.
I don't have any experience editing porch values at 31khz (your desktop resolution), however I don't know why the porch value edits woudln't affect the image. But since you are able to move it at 15khz it sounds like you know what you are doing.
I'm assuming if i paste my porch values in mame.ini under monitor_31, it wont carry over the to 15khz games.
You have three crt ranges that you are defining:
crt_range0
15250-16500, 40.00-80.00, 2.187, 4.688, 6.719, 0.190, 0.191, 1.018, 1, 1, 224, 288, 448, 576
crt_range1
23900-24420, 40.00-80.00, 2.910, 3.000, 4.440, 0.451, 0.164, 1.048, 1, 1, 320, 384, 0, 0
crt_range2
31000-32000, 40.00-80.00, 0.636, 3.813, 1.906, 0.318, 0.064, 1.048, 1, 1, 480, 512, 0, 0
crt_range0 is for editing how you want your 15khz games to look, as noted by the horizontal frequency range in bold.
crt_range1 is for your 24khz medium resolution games, again as noted by the horizontal frequency range in bold.
crt_range2 is for your 31khz, high resolution games (and as you've selected, your desktop). Again note the horizontal frequency range in bold.
Take the porch values that get you the white boarders at each of the resolutions: 640x480 @60p for
31khz, 640x320 @ 60p for
24khz games, and either 640x288 @ 53p
or 640x256 @ 59p for
15khz games.
write them down and edit the porch values as shown in bold below:
crt_range0 15250-16500, 40.00-80.00,
2.187, 4.688,
6.719, 0.190, 0.191, 1.018, 1, 1, 224, 288, 448, 576
crt_range1 23900-24420, 40.00-80.00,
2.910, 3.000,
4.440, 0.451, 0.164, 1.048, 1, 1, 320, 384, 0, 0
crt_range2 31000-32000, 40.00-80.00,
0.636, 3.813,
1.906, 0.318, 0.064, 1.048, 1, 1, 480, 512, 0, 0
The first bold number on each line is your front porch value, and the second bold number is your back porch value.
Should i ditch the trisync profile and just go with a arcade_15 profile, or is that defeating the purpose of have a tri-sync monitor?
Yes, don't ditch it. The whole point is that you tell GroovyMame which resolution to choose with which game. It will compare the games video data (resolution, refresh rate, etc), and pick the matching resolution, refresh rate that your monitor has.
I'm very keen on seeing how this works for you, as I am contemplating picking one of those up myself.