Saturday, October 2, 2010

Overclock a Dinosaur

Since I messed up my computer with the whole cpu cooler fiasco, I've had to go back to my old PC. The specs are as follows:

Processor: AMD Sempron 2500+ @1.5GHz (166MHz * 9.0)
Motherboard: ASRock K7VM3, Rated FSB: 333MHz
Memory: 2x 1GB DDR @200MHz
Graphics: Inno3D GeForce 6600 @300MHz, 256MB @500MHz
Hard Drives (2): Seagate Barracuda 7200rpm 200GB + 80GB (P-ATA IDE)
Optical Drive: LG Super Multi DVD re-writer
ISO 300WSwitching Power Supply
Operating System: Windows XP Service Pack 3

For the technologically challenged: it's crap. These days you can get a fridge with more processing power than this thing. (ok I'm over exaggerating, I'm actually writing this blog post on it within Firefox 3.6.8 while playing music through iTunes 10)

Being used to my "reasonable" Core 2 Duo and HD4870 I was extremely dissatisfied with the above setup. Tests showed a very sad eight frames per second (average) on lowest graphics settings in Crysis @800x600, and less than one frame per second when blowing up buildings with the rocket launcher, physics set at medium. Enabling shadows halved the average frame rate to around four frames per second. Dropping screen size below 800x600 did not make much of a difference, the issue of pixel count giving way to other factors such as shaders and polygon count that may not rely on screen resolution (as far as I know, just speculating here).

Since this old brontosaurus of a pc isn't really of much value to me (besides sentimental value. I wouldn't sell it to anyone, although I doubt I'll get anything for it if I did) I thought I might take a stab at this whole overclocking thing. I've overclocked my HD4870 before, but this is the first time I'll be overclocking a processor.

To all you folks out there who think overclocking is a fun experience (actually it isn't very fun) and a quick way to get more power without buying new hardware, make sure know what you're doing before you do it, or just don't do it. Don't say I didn't warn you...

Since this old rig (oil rig?) is old, none of it's components really output an impressive amount of heat, giving me good headroom for bumping the hertz up a little bit. Even with really lame stock coolers, the processor usually didn't go higher than forty under load, and the GPU stuck around the sixties, also not changing much under load. I didn't burn my fingers on the GPU like I always did with my 4870 every time I stuck my hand in the case.
(Temperatures are in degrees Celsius, for all you Americans reading this, convert!)

the Overclock:

The ASRock K7VM3 has a feature they call Hybrid Booster "safe" overclocking. This allows for easy changing of the bus speed within BIOS. Over-enthusiastically I took a huge leap from a bus speed of 166MHz to 233MHz. NOTE: This is a stupid thing to do! Always overclock in small increments, like 5MHz, and every time rebooting and checking up on how the computer does under the new speed. Thankfully ASRock's "safe" overclocking did not allow my idiotic jump, and promptly reset the bus speed.

I still didn't quite take the 5MHz advise very well (and by no means am I encouraging this behavior) and increased it in 10MHz steps. And I don't know if the Crysis CPU Benchmark constitutes as a CPU stability test, but it definitely allowed me to see that the overclocking was working.

The K7VM3 uses jumpers to set the CPU multiplier. The manual shows, in a rather confusing way, where to put the jumpers to get the desired multiplier. By default (with no jumpers) the multiplier is at 9.0, and can be increased (or decreased) in steps of 0.5, up to a whopping 24. I set it to 10.0 and very excitedly switched it on and... It didn't work.... it still showed 9.0 no matter what I did. Sadly, this specific processor is locked to 9.0 and cannot be changed without possible mutilation. I'm not going to try that!

I stopped at a bus speed of 200MHz, resulting in a substantial CPU clock speed increase of 300MHz to 1.8GHz. Very happy I tested it on Crysis and saw an increase of one frame per second in the CPU benchmark! w00t! :)

To overclock the GPU was much easier, but unfortunately not as fantastic. Using RivaTuner, I was able to push the core clock speed by 17MHz (yippee....) and the memory frequency by 14MHz (wow....). Not all that great of an overclock but an overclock nonetheless.

However, I am a little concerned about the current stability of the system. Since the overclock, Firefox has randomly quit (which it never does) twice and earlier the computer reset without warning, Windows later telling me that there was a serious error and had no explanation as to what happened. I'm glad nothing has happened while writing this blog...

I will do some tests with Prime95 soon and will post the results. I don't know if I want to see the results...

Other tools used: CPU-Z and GPU-Z

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