For SVCD, get a faster CPU, simple as that. The A7V will take up to a 1.2gig Athlon with 200 FSB ( I had one recently myself) I now have an Athlon 1800+ and takes about 7hr to encode a 2hr movie as per my tutorial. Amount of RAM is not so important.
Read the tut and do the few things l mention at the start there like turn off screan saver, virus checker, etc.
Depending on the movie, you can select CBR rather than VBR 3 pass and end up with similar results but normally on an extra CD. A 43min episode of Star Trek - The next generation encoded as CBR or 3 pass VBR and to fit to 1 80 min CDR will have similar quality. The CBR takes 1/3 the time to encode compared to VBR 3 pass. But a 100min movie encoded as VBR 3 pass will be a lot better quality than a CBR of the same, both on 2x80min CDR's. Put the CBR on 3 CDR's and then they will be similar.
VBR will produce either smaller files than with CBR or have a higher bitrate (and better quality) if limited to the same number of CD's. I hope I havent confused you there.