well honestly the default video card will probably be fine. if it can push 1600x1200 then 1368x768 will hardly be a stretch for it.

But if you do want to upgrade you are unfortunately stuck with eBay or the like, as the 9200 and 9800, the last AGP4x cards being made, are no longer in production.

I believe refresh rate is a term for CRT's, as the electron gun must hit every phosphor every so often to "refresh" it so it doesn't fade out.
I suspect flat panel technology uses a different method which does not involve any sort of refresh rate.

Click to expand...

Actually the term is Response Time, the time it takes for the molecules behind the RGB filter to align for any given color combination. Typically its around 5-15 milliseconds. There is a way that that translates to Hz, hence why if you have an LCD display you can still adjust it to refresh from a typical 60-75Hz. Average is 60Hz.