AMD kit has always benefit from a bit of fiddling, and at stock there's always a little bit of performance missing. AMD kit has always tried to push the boat out - to mixed success - and try a few different things. However much of a shocker Bulldozer and its successors turned out to be, AMD tried a different approach with it, they got 8 cores to the mainstream a long time before Intel were forced to, they got 5GHz boost clock years ago, but you can't just "drop in and go" with AMD (even now with Ryzen) and it's seen as inferior as a result.
To be fair with the 2600(X) builds I've done lately - I've literally dropped it in, changed two settings in the BIOS (one XMP which I'd either do or setup RAM manually anyhow even on Intel) rebooted and it is all ready to go. Two more minor tweaks, if desired, to enable certain performance enhancements and they boost close to the good manual overclocks without any fuss - but the people I've built them for aren't gamers and just want solid, stable stock frequency.