I used to rip DVD movies in 4.7GB compressed and also into 8.5GB dual-layer and it can take anywhere from 20-40 minutes to rip to hard drive and then to disc. I have not ripped DVDs in a long time since I have switched to blu-ray and HD recently. I HAVE used DVDFab for DVD movies though. I have no blu-ray burner yet in my PC. However, it will probably take quite a while and taking 2h15m is not unusual for 50GB which is about 6 times the size of a dual-layer DVD.
What are you system specs - CPU, video card, RAM, motherboard and what OS are you using?