Martial, That is a tough question and has a lot to do with drivers, opinions and experience. I guess you could ask what cards the developers used on their development/testing systems. I have used Carrara 3 with an ATI 8500 on Mac with no problems. I use it now on a Dual G5 Mac with an Nvidia FX 5200 with no problems. My PC has an Nvidia GF4 TI 4400 w/128mb RAM with no problems either. Of course always make sure you have the latest official drivers. In doing troubleshooting for some of my clients systems I found that many problems were caused by them using 3rd party, hacked, or over-clocked drivers. Go with the latest Nvidia or ATI drivers that are official release drivers. On Windows it seems to be even better if those drivers are WHQL certified, but sometimes they are and sometimes they are not. Beyond that other things I have seen slow down graphics apps had to do with the motherboard and chipset. Use a well known Motherboard and a proven Chipset. HTH, Paul