I live in Port Said and i work in Marsa Alam, the distance is 750 km and the speed limit as of Ismalia is 90 km/h until you reach Marsa Alam.
I have tried (once) to follow the law and drove my car @ 90km/h and it took me 13:30 hrs to reach my destination.
But when i drove according to the actual road status - sometimes- at 220 km/hr but the average is 160 km/h i did it in 7 hours including breaks
There are some places you can't keep 90 km otherwise you could sleep and cause a disaster like Zafarana-Hurghada road and there where they put their Radar to catch speedy cars specially during Holidays when people are driving to Hurghada to spend their vacation. Most of the time the Radar is placed around 15 KM before you reach Ras Ghareb and some times they move it in the middle of the road between Zafaerana and Ras Ghareb so everyone take care please.
Wa alsalamo alikom wa rahmat allah wa barakato.:) .