anything is possible but generally 4x with imgburn seems to yield best results for most ppl. Media is a factor as well - verbatim is what I recommend but others will say they had success with other brands.
burner has an impact as well. for about 70 discs of a 100 disc spindle i had about a 40-50% fail rate (it would say successful but the Wii would give me the question mark sceen) burning at 4x. i thought it was just a junk spindle. ended up getting a new burner because i wanted to burn some DL stuff, and since ive started using the new burner ive gone through the rest of that spindle and part of a new one with 0 fails burning at 4x i had an older AOpen drive, upgraded to a Pioneer DVR-112D and love it. the spindles were Memorex DVD-R 16x (RITEKF1). not great media, so thats why i was surprised when it changed so drastically with the new burner. everyone else had said "get better media, get better media" Verbatim and Taiyo Yuden are the best media brands available, and if you have problems with other media, and a drive upgrade is out of the question, definately try better discs. but as to speed, 4x is the most reliable no matter the burner/media combo
