if it doesnt say what the refresh rate is for, it probably is for vertical - the whole plan is, that something on the monitor has to sync as the "guns" pass through the screen. Most monitors go for the vertical refresh, whether they say so or not... i.e. 1024 x 768 @ 60 Hz, 800 x 600 @ 55 Hz, etc... Monitors manuals will always sell on what resolutions they can do, and at what refresh rate, not to mention dot pitch size, and monitors "visible" size - you can have a monitor that is 27", but only have a "visible" size of 24".

Check your monitor manual - most are going to "auto-sync" - they didnt do that way back - I always set my vrefresh to 60, and the "auto-sync" on my ViewSonic will always alter it to what it likes, sometimes you just have to give it a "starting point" to work with.

Try the vrefresh=60 -=- and see if it, not only works, but that it changes to what it wants, and can use, on its own.

Ms. Cuddles