I run a dual monitor setup (EQ2 on one, ACT+internet on t'other) and don't notice any lag, but that is because I dial EQ2 all the way back for raids so that everything is silky smooth.
I assume you have got by the first hurdle of turning your log file on (/log)?
You can also parse files after the raid by going to the import/export encounters, select the date ranges you want to search for in the log file, then select the file (it will be in a folder called logs in the eq2 directory or some such)
Once you have the encounters up in ACT there are a couple of ways you can navigate, using using the expandable menu window on the left, or the table on the right. Clicking on someones name in either window will bring up a number of options to look at (all outgoing is probably the one you want); double click that and you'll get a rundown of all the things you did that caused damage to the mob, including a pie chart. You can right click any of the images in ACT to export them to an image file, which can then be hosted somewhere like Imageshack.
Additionally you can go deeper than just looking at rundowns, but can see the individual damage of every skill (by clicking the skill in either the right or left windows). That gives a tabulated view of the statistics concerning every time you used that particular skill, a bar graph below of damages of all the times you used is, light red bars are crit-hits.
You can also change the info displayed in the main views in the table setup tab, options like damage% and to hit% numbers can be selected here and will be shown on the main tab.
Just press stuff that looks interesting till you find your way around

Its what I've always done.