He didn't say 4790k. He mentioned the non-k sku that is locked. They can be purchased used on eBay for around $150 and will outright beat FX chip merely due to it's ring bus architecture, let alone single/multi core performance. It's a viable upgrade for any use case, coming from the AM3 platform. My recommendation if purchasing used, is to purchase a locked sku so your are guaranteed a working chip. Purchasing used unlocked k sku's aren't recommended as you have no idea how much voltage the seller had been running through the processor from overclocking.