Kill all nonesential apps before running flask. Lower some quality settings. Use mmx decoding as it is fastest and you can't tell the difference. Reduce the size of the output video. Crop the black borders.
Give me fuel, give me fire, give me that which I desire.
DivX is a complicated video algorithm & needs alot of cpu resources. it exists know a FlaskMPEG AMD & Intel optimized version (for SSE & SSE2 iirc). nevertheless you need a huge cpu like a AXP 2100+ or an intel p4 2.4 to reach 50fps encoding. (same cpu resources needed likewise 3DStudio Max or so) the best at this time staying a p4 1.6A@2.8 for a modest amount.
i've plugged my home blower to my case ... dunno what happen ... that works?!?