Time frame to crack 8 character md5 hashes

What kind of time frame am I looking at to crack an 8 character md5 hash against a rainbow table? (1 GPU card, 7970)
Would 32GB vs. 64 vs. 96 Ram make a huge difference?
Would 7200RPM drives vs. say 4 512GB SSD in a raid 0 array have a huge differnce? Also how about hardware raid, vs. software raid?
Thanks 
Would 32GB vs. 64 vs. 96 Ram make a huge difference?
Would 7200RPM drives vs. say 4 512GB SSD in a raid 0 array have a huge differnce? Also how about hardware raid, vs. software raid?

