An I3 will do the job. Spend your money on video cards. Tom’s Hardware ranks the I7 and I5 as pretty similar for gaming.
Tom’s Hardware (dot com) has some good recent build-off data for several different price levels.
Thanks, I’ve already got a good video card that will run 4 monitors out of one slot. It’s a PNY Quadro NVS 440. It’s mostly a financial card for online trading. I’m just going to migrate it over to the new build.