Someone was able to get the beta running on a MacBook Pro with 9400M graphics (
see here). A quick Google search implies the 3850's performance isn't dramatically lower than the 4850, so there is reason to think it may be playable, at least with lower graphics settings and/or resolutions.
There should be a demo released at some point, if nobody replies with feedback about that card, or something comparable.
Zolee;
Did it help to set the graphics and texture quality to medium or low? There is a known issue that can cause a crash entering RTS (can also be caused on a laptop if the game is running off the integrated graphics rather than discrete), so your stability problem may not have been entirely due to the system specs.
