If you want toying around with the your CPU buy this, it is it's purpose .
8 April 2014
Summary: Little, old but still very powerful CPU , with the ability to Overclock to 4 - 4.1 Ghz and with any luck unlock the other 2 cores this CPU can go head to head with most of the new CPU architectures, and believe me it can take abusing quite a lot.
This has been my all around Fav for three years, can't beat it's head room.
7 March 2014
Summary: I build high end PC's with speeds up to 5.5 GHz for games, CAD, and Simulators. and although I have these very systems running in my Home/Office - It's the AMD Phenom II X2 555 Black Edition I choose for my personal system. I pair it with the M4A89GTD Pro/USB3 from ASUS and HAF Tower, 8GB RAM and a smiple air cooler. Why? simple, I multi task a lot. With the 555 unlocked and running four cores it's bullet proof. The 555 BE is like no other.
Summary: The ASUS mobo I have this in allowed me to unlock the 3rd and 4th cores with a single key press. It runs stable with all 4 cores running at stock speed. It has stability issues when even slightly overclocked, which I traced to Core 3, which is why it was sold as a 2 core. I was happy just having all 4 cores at stock speed, it definitely saved me money. This was my 2nd great experience with an AMD CPU, so I stuck with them when I upgraded last fall.
Summary: I know it's not a intel i5 or i7, but these make for a awesome budget build. Mines running strong and pretty cool as well. I've overclocked to around 4.4ghz with no issues using cool master direct heat pipe 120mm cooler.
Summary: AMD makes great processors. I like the Phenoms because they are unlocked. You can activate more cores, overclock it, and change any settings imaginable. If your lucky you can have a four core processor for the price of a two core processor. If your not lucky, you still have a really fast and powerful chip.