Overclocking the AMD Phenom II 940 Black Edition Processor:
It’s been just a hair over a week since I built my new system, and I initially wasn’t planning to overclock, but that allure of the “Black Edition” and the unlocked multiplier was simply too much to resist.
I will say this – overclocking the 940 is dead-on simple, as long as you don’t plan on pushing it too far. I’m what you could call a “conservative overclocker”. I tend to only push as far as I feel comfortable with, and only just enough so that I feel like I’m getting the most out of my system.
The default speed of the Phenom II 940 BE is 3.0GHz – I’d read around the web that most people were able to hit 3.2-3.4 quite easily even on stock cooling. I started off myself with the stock cooler, but I ended up pulling my OCZ Vendetta out of my old Intel rig (and re-installed the stock Intel HSF in that box) and installed it on the Phenom II along w/ some Arctic Silver 5 thermal compound.
I was able to hit 3.4GHz on stock voltage with the stock cooler – any higher was going to need some more voltage, and I didn’t want to increase the voltage w/ the stock cooler since my temps were running just a tad high (peaked at 59C @ full load under Prime94 x64 w/ stock cooler). After putting on the OCZ I discovered much lower temperatures, but still hit that same wall past 3.4GHz. I did try a small voltage injection (up to 1.425 up from 1.325 stock) and I was able to hit 3.6GHz – Prime stable. My temps at 3.6GHz were around 57C under full load – still a tad high for my taste.
I decided to drop back to a stable 3.4GHz at stock voltage, since running 3DMark06 and some basic “eye benchmarks” with Counter-Strike:Source’s “Video Stress Test” and watching FPS in Unreal Tournament 3, it seems I hit a GPU bottleneck after 3.4GHz – my 3D Mark score barely changed, and my max FPS in CS:Source and Unreal Tournament 3 barely changed (if at all).
Although not the main purpose of this post, it’s also worth mentioning that I was able to get quite a bit more out of my ASUS ATI HD4830 – after reading some reviews online, it seems that most folks were easily getting up to 700MHz on the GPU and quite a bit more on the RAM too. The stock speeds on this card are 575MHz for the GPU and 999MHz (1998MHz Effective) on the RAM. I simply used the “Auto-Tune” feature in the Radeon Control Center and I was able to get up to 700MHz on the GPU and 1185MHz (2370MHz effective) for the RAM on that 4830 as well!
Here are my basic 3DMark06 results at 3.0GHz (Stock/Stock GPU), 3.4GHz (OC on CPU and GPU) and 3.6GHz (OC on CPU and GPU):
Fully stock speeds – 3.0GHz CPU (Stock Voltage), 575MHz/999MHz on the 4830:
Stock speeds:
11722 3DMarks
SM 2.0 Score 4426
SM 3.0 Score 5160
CPU Score 4174
Overclocked Results:
3.4GHz CPU (Stock Voltage) 700MHz/1185MHz on the 4830:
13917 3DMarks
SM 2.0 Score 5310
SM 3.0 Score 6227
CPU Score 4648
3.6GHz CPU (1.45 V Core) 700MHz/1185MHz on the 4830:
14037 3DMarks
SM 2.0 Score 5321
SM 3.0 Score 6222
CPU Score 4865
So, as you can see, I pretty well hit a wall w/ my GPU past 3.6GHz (which is still a respectable “wall” for a $100 GPU in what’s essentially a “Workstation” rather than an all-out Gaming rig), so rather than risk my CPU with added voltages and extra heat, I’m going to simply run it at 3.4GHz w/ 29C Idle speeds (I have “Cool ‘n Quiet turned *off* by the way – no throttling for me please!), and 50C Load speeds and just be happy! I have achieved maximum performance for my rig, and that’s all I cared about.
I do want to add that this is the first time I’ve had a “Black Edition” from AMD, and I surely never could afford an Intel “Extreme Edition”, so I’ve never had an unlocked multiplier before. It really does add some peace of mind when overclocking, because you know you aren’t unnecessarily stressing out other system components – you’re simply increasing clock-speed.
One interesting take away is that apparent 3.4GHz on stock voltages that I encountered. It seems to be echoed across the web as well, so perhaps that could be an indication of “stock” 3.4GHz chips coming out of AMD soon!
A 3.4GHz stock chip would for sure put AMD in direct competition with the Intel Core i7, *especially* if it’s an AM3 chip paired up w/ speedy DDR3 RAM.
The only other benchmark I’ve ran besides 3DMark has been Cinebench, and @ 3.4GHz, I’m crunching just above the Core i7 920 on Cinebench R10.
Just some food for thought, and I’m very glad that AMD has come back with some real competitive chips again. I love having AMD inside my case!

Written by jaysonrowe on February 7th, 2009 with 1 comment.
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