Just picking a random CPU "Opteron 6174 12core" has a hashrate of about 30mh/s when it comes to hashing sha256, the oldest running ASIC today would maybe antminer S7, if you look around you may find it for free, Antminer S7 does 4.7th/s , 4.7 tera is 1000000*4.7 = 4,700,000mh/s, in other words, that obsolete miner is more powerful than 150k Opteron.
The latest-gen miners do 100-200th, that's an order of magnitude higher than any combination of any CPUs out there, Bitmain can make in a single hour what Intel and AMD will never make in a 1000-year if the challenge was hashing sha256 using CPU vs ASICs.