I have an old iMac with 10.3.9 on it. It has 1 GB of ram, 55 GB hard drive space etc, G3 processor. I would like to install OS 10.4 Tiger on it but I noticed it said that you need built in FireWire. This iMac does not have built in FireWire so would I still be able to upgrade this iMac to 10.4? Is the built in FireWire a recommendation or requirement?