Making Lemonade: Overclocking Your Locked AMD Processor

Readers of this site are probably well aware of the overclocking potential in AMD’s Phenom II processors. Through CPU reviews, performance comparisons, picture stories, and “How To” guides, Tom’s Hardware has highlighted the hidden potential within these processors and detailed how to attain similar results at home.

From our explorations of the AM2+ or AM3 platform, using basic or extreme cooling, the one constant has been the use of a Black Edition Phenom II—and for good reason. These “unlocked” processors are specifically targeted at enthusiasts who want to squeeze more performance out of the product than they paid for.

This time, however, we’ll specifically look into overclocking a “locked” processor. We chose the AMD Phenom II X3 710, a roughly $100, 2.6 GHz triple-core chip. Though it certainly doesn't lack stock performance or core speed potential, a locked processor such as this one offers far less overclocking flexibility.

What exactly is a locked processor? Specifically, we’re referring to the “locking” of the CPU multiplier and, in the case of this AMD processor, the CPU VID (voltage ID). Actually, both values can be reduced, but they’re locked from being raised above their stock base value.

Taking a look at the equation core speed = CPU multiplier x reference clock, you can see that eliminating the ability to raise the CPU multiplier means any increase in core speed will need to come from raising the reference clock. This will, in turn, raise the HT (HyperTransport) link speed, northbridge speed, and memory frequency, which are also based on the reference clock. If you need a refresher on terminology or calculations, take a look back at this How To: guide.

To cool our retail Phenom II processor, we set the boxed cooler aside and used the Xigmatek HDT-S1283. However, to have any hope of pushing this processor up into the same range as a Black Edition, we also needed a motherboard capable of running a high reference clock. As seen in this motherboard roundup, the MSI 790FX-GD70 stands out as a winner in this area and should allow us to push this CPU to its air-cooled limit.

In this story, we’ll highlight a few different methods of overclocking our locked processor, including conventional BIOS overclocking, AMD’s OverDrive utility, and the 790FX-GD70’s nifty OC Dial. We’ll walk through these three methods, comparing both the experience and results achieved. Finally, we’ll take a brief look at the performance gained by overclocking the CPU, northbridge (NB), and memory.

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  • radnor
    This is a great article, that so far nobody posted nothing. One thing failed tough. You shoudn't have used a high end board you should do it on a normal or low end mATX board. My old brisbane (x2 4800+ 2.5ghz) is still rolling at 3Ghz with a mild bump in voltage.

    That CPU is in the same board (M2A-VM) and gave it to my little brother. Still works will work :) 500 Mhz stable , low voltage , not burning hot , Overclock, in a mATX motherboard.

    Maybe you should aim showing that to peeps. Pick 3 low-mid boards, with 3 CPUs, 550 BE, X3 710 and a 7850. They are all fairly cheap. Then do it again for Intel counter parts, with crappy boards.

    I would love to help you guys on that, but i really don't have the gear to do it. Like this article showed you can really get some very nice value from low-mid end cpus. Just use mATX boards.
  • wild9
    Finally, we’ll take a brief look at the performance gained by overclocking the CPU, northbridge (NB), and memory.

    I wonder how many AMD fans have been waiting for that..I bet it's quite a big number. Myself included :)
  • Reynod
    Nice article Paul.

    Well done.
  • Solitaire
    Nice article this! Thanks Paul :)