Demonic Heart :
http://versus.com/en/asus-m5a99fx-pro-r2-0-vs-asus-sabertooth-990fx-r2-0
Read this ^
Hmm
Have you tried overclocking on your sabertooth?
I've overclocked my m5a99x evo...
Listen... the sabertooth is undoubtedly the better motherboard, it's well regarded as one of the top 2 or 3 overclocking boards for the FX series cpus... and is easily the most popular of those 2 or 3. That said solid ram, solid psu, good case airflow, a good cpu cooler and a great cpu all can work wonders on an overclock as well. Here is an 8320 hitting 5.3ghz on a slightly inferior board. It's stable 24/7 at 5ghz on this board too. Asus makes some amazing boards, and the vrms on all 3 of the boards mentioned here are all top of the line.