It maybe a driver issue. Is your Windows fully updated? Does Macrium have a separate updated ISO for the boot CD? Acronis periodically updates that separate from the actual program.
Joe
With Acronis that size takes about half an hour at most to a USB 2 drive. If this is a desktop try using a port on the back sometimes on old machines the ports on front are USB 1.
Joe
I would strongly recommend you try Acronis TI. I have relied on it for years and consider it the bet in its field. It is not expensive and you can download a fully working trial copy.
I'm still using Acronis TI 2010 I boot from CD and make image or restore that way. I have my HD partitioned with system on one and data on the other.
Joe