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Socket AM3: AMD's Phenom II Gets DDR3

Modding And Overclocking–Doable?

Our first thought after hearing that AMD wouldn't be launching a Phenom II X4 940/920 equivalent for the AM3 platform was, "what about all of the enthusiasts who've been eying those high-end models and still want to experiment with DDR3 memory?"

We knew we had a Phenom II X4 940 in the house that didn't scale very well and would likely be replaced soon by another chip that would ideally have more headroom built into it, so we decided to try "creating" a 938-pin AM3 chip out of our 940-pin AM2+ sample. After all, the silicon under its proverbial hood was the same–the only difference was its interface.

So, using a mechanical pencil, we bent the two offending pins back and forth until they snapped off. The chip now fit into our AM3 test platform, albeit not flush due to the metal nubs where each pin broke. Unfortunately, the modded processor would not POST at all, forcing us to conclude that the task wouldn't be as easy as popping off pins. It's truly a shame that enthusiasts can't get access to AMD's AM2 pinout, which would describe the exact role of each pin rather than force us to guess. The most recent tech doc publicly-available relates to the old-school Socket 940 interface.

Wondering if we'd just nuked a perfectly good CPU, we moved the Phenom II X4 940 back to its AM2+ board. Lo and behold, it still ran fine, without any immediately apparent issues.


Thwarted in our efforts to turn AMD's flagship Phenom II into an AM3-compatible part, we switched gears to the Phenom II X3 720 Black Edition. AMD had suggested to us that the Phenom II X3 would theoretically be more receptive to overclocking since it isn't as complex as the quad-core models.

Indeed, using Asus' M4A79T Deluxe, we were able to get the triple-core chip running stably at 150 MHz faster than our X4 940, right around 3.8 GHz.

With a price tag set at $145, this one looks like a no-brainer for enthusiasts who already own a 790-series motherboard and DDR2 memory. Even the Core 2 Duo E8500 we've tested here still costs $190. The Phenom II X3 is going to perform better in apps optimized for more than two cores and it'll hold its own in overclocked comparisons to Intel's Core 2 lineup.

Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.