Hello sibbell,
Welcome to the HP Forums!
I understand the Officejet 8600 prints slow. I will do my best to assist you! How is this printer connected? Wireless or USB?
What is your operating system on your computer? Windows or Mac?
What type of paper are you trying to print?
Try printing a "Self Test Page" from the printer, this would indicate if this is a hardware or software related issue. Please follow this HP document here.
Looking forward to hearing from you.