Overclocking and more

C3 Revision OC’ing

If you’ve followed our Phenom II CPU reviews over the past 11 months, you’ve no doubt noticed that all of the Deneb CPUs we’ve tested have hit a wall right around 3.7-3.8GHz. Our 140W Phenom II X4 965 sample topped out at 3849MHz, 11MHz shy of our 955’s top speed of 3860MHz.

For comparison’s sake, our original Phenom II X4 940 Black Edition maxed out at 3.745GHz.

Even the dual and triple-core Deneb CPUs we’ve tested haven’t scaled any further than this. The X2 550 hit 3.829GHz, while the X3 720 couldn’t run any further than 3807MHz.

We could clock a couple of these CPUs at speeds approaching 4GHz, and even run a few benches at those speeds (the 955 could actually run Crysis at 4012MHz with 100% stability) but we couldn’t maintain complete stability with all the benchmarks we use for testing. Any app that pushed the CPU (Prime95, Cinebench, etc) would cause a BSOD, or the system would lock up at one point or another.

Not so for the new C3 Revision Phenom II X4 965. This CPU OC’ed further than any AMD CPU we’ve ever seen.

Whereas the C2 Revision Phenoms we’ve tested in the past maxed out in the 3.8GHz range with complete stability when running over 1.5V of juice to the CPU, our C3 Revision Phenom II X4 965 Black Edition chip was able to run at 3.8GHz at stock voltage. More specifically, we hit 3857 (19.0x203) at stock voltage with our 965 BE sample:

3857MHz at 1.36V

This is simply an incredible difference that any OC’er will appreciate. And remember, since we’re running at stock voltage, the chip is also generating significantly less heat at that 3.8GHz than our older C2 revision Phenom CPUs which were running at higher voltage.

So how far were we able to push our CPU when we upped the voltage? We managed to hit a top speed of 4066MHz (19.0x214) at 1.52V.

4066MHz, SWEET!

The CPU could run at higher speeds, but again, we couldn’t maintain 100% stability.

All CPUs were cooled with Zalman’s CNPS9700-Cu. We’ve included all benchmarks at 4066MHz so you can see how much of an impact our OC has on performance. You’ll also want to check out the temps and power consumption results on page 4 of this article.

Spotting a 125W chip

If you want to pick up one of the new 125W Phenom II X4 965 chips with AMD’s latest C3 revision specifically, your best bet is to look really close at the CPU’s OPN number. The OPN # for the new C3 revision CPU is HDZ965FBK4DGM. The “M” at the end denotes the new C3 revision.

The OPN for the original 140W part is HDZ965FBK4DGI. This is the CPU that you don’t want, so make sure the OPN # has an “M” at the end.

125W Phenom II X4 965 (left), 140W (right). Note the M at the end of the OPN on the 125W CPU (the OPN is the first line just below the Phenom II branding)

Many retailers also denote the CPU’s TDP under the specifications listing. Newegg for instance does this.

Speaking of retailers, AMD charges the same $195 for the 125W Phenom II X4 965 Black Edition, so you hopefully shouldn’t have to pay a price premium at the retail level for the new 125W 965 CPU.

AMD will begin replacing additional Phenom II models with the C3 revision in the coming months, so if you’re an AMD enthusiast but can’t afford to splurge for a new 965, you may want to keep your eyes peeled for 955 and 945 models utilizing the C3 revision in the near future.

AMD wanted to focus on the X4 965 Black Edition at first in order to bring its TDP down to 125W as quickly as possible. OEMs and system integrators will likely gobble up the new CPU, as the original 965’s 140W TDP may have been too high for them to integrate into existing Phenom II systems. With the addition of the 125W Phenom II X4 965, they don’t have to go to the expense of testing and qualifying the 140W part. They’ve now got a drop-in replacement for the 955 that should run well with existing chassis/cooling designs.