It had an Intel 8088 processor (the 8-bit wide version of the 8086). ISTR that it ran at 4.7MHz.

"A fully equipped IBM Personal Computer, with 64 Kbytes of memory and a floppy disk, cost $2880"

"The IBM Personal Computer was given its press launch in New York on 12 August [1981]"

Both quotes from ISBN 0-465-02989-2

I found the following links, too:

http://www.apple-history.com/lisa.html
http://www.digitalcentury.com/encyclo/update/pc_hd.html