My Experience: Overclocking My Computer

This is my documentation of another attempt to overclock my processor. I happened to have a fairly overclockable rig on my hands but I was still a newbie when it comes to tweaking computers for maximum performance. So did I achieve my goal or fail miserably? Read this article to find out.

Overclocking is an act practiced by many computer users in order to get the most performance out of their money. By definition, to overclock is to run a component beyond its manufacturer’s recommended frequency. It will make the computer go faster but at the cost of more heat and less stability, and it can potentially permanently damage the component and things around it. I am definitely not a hardcore overclocker (more like a noob), but I tried to do so anyways right after I bought my current rig since so many people seems to be overclocking and I didn’t hear too many “horror” stories about how sparks flew out of people’s cpus. Overclocking actually isn’t very difficult, if the right components are in place. It took me about five minutes to figure out what to do to speed up my computer.

Here is some background information for those who are not into computers. There are basically four things in a computer that can be overclocked: the cpu, the memory, the graphic card processor and the graphic card memory. The cpu and memory are usually overclocked from the motherboard BIOS. That is, if the BIOS has those features. The graphic card is easier to overclock because a person can easily adjust the frequencies from within the operating system. All components can be overclocked to a certain point, but how much a specific component can be overclocked depends on;
1. Cooling. How good is the ventilation of the case and the hsf on the component? Better cooling usually mean better results, and it prevents the component from dying due to excess heat.
2. The component itself. Certain processors, memory, and graphic cards can overclock better than others. For example, the mobile XP2500+ is known as a great overclocker even with generic heatsinks, while you’ll probably won’t get much from a Prescott based Pentium 4 without some hardcore cooling. This is obviously due to the difference in design between products. Certain versions of one products also might overclock better than another version (ex cpu manufactured on one week maybe different than a cpu made on a different week).
3. Other components in your computer. If you try to overclock the cpu or the main memory, the motherboard is very important. The motherboard has to support frequency and voltage adjustments for overclocking, and also certain motherboards overclock better than others.
4. Luck. Even though two components might look identical, they might not overclock the same. One might respond to the increased frequency better than the other, so cross your fingers when buying stuff and hope you get a good part.

So that’s about everything. If you read my first computer article, you know that I have tried overclocking soon after I built this computer, but I backed off when the temperature got near 60 degrees Celsius on my processor and that it wasn’t entirely torture test stable. Well, I upgraded my heatsink on the cpu recently and one of the reasons why I upgraded was that I wanted to overclock again. The new hsf dropped my rig’s temperature by a bit, so I think the computer is ready to attempt at running at XP3200+ speeds again.

For those who haven’t read my other computer articles, I have an AMD Athlon XP 2500+, non-mobile. It is based on the Barton core that has 512KB of level two cache. It has a multiplier of 11 and front side bus of 166Mhz to make it run at a total of 1833Mhz (11 x 166) with a voltage of 1.65volts when at stock. Back in the days (in the earlier parts of 2004), the 2500+ was quite popular because it was cheap, had an adjustable mutiplier, and can easily be overclocked to the level of the 3200+ (which runs at 11 x 200 = 2.2Ghz), which happened to be the AMD flagship processor at that time. People liked the idea of paying a fraction of the price and still get the peformance of the top of the line processor with just a little bit of tweaking. I bought mine in July, which means my cpu was a late production model that had locked multipliers, but it didn’t really matter to me since I don’t plan to overclock the processor by a lot.

Anyways, to overclock the processor, I had to go into the BIOS (which stands for basic input output system, I believe) during bootup of the computer. In there, I have to adjust the FSB frequency and the core voltage. My motherboard, the Soltek 75FRN2-L, uses the nForce2 Ultra chipset, which means it has all the features I need to overclock. A processor’s clockspeed is determined by the FSB speed times the multiplier. My cpu’s multiplier cannot be adjusted, so the only thing I could do was try to crank up the FSB. So I went into BIOS, into the appropriate menu, and changed the FSB from 166 to 200. Then I went into another menu and changed the core voltage from 1.65 to 1.70. More voltage tend to increase stability in an overclocked processor, but it also produces more heat. The setting I had at that point was the setting that worked when I first bought the computer, so with the newly improved cooling, I see no reason why the setting wouldn’t work. I saved the settings and the computer rebooted and went into Windows.

To test for stability, I used Prime95, which has been very useful to me since it helped diagnose the hardware problems my system had recently. It stresses the processor and memory a lot so that any big problems will cause an error in the program within two minutes. The last time I overclocked, Prime95 was able to run more than six hours before an error occured, which is pretty good. I was just going to settle for ten minutes without an error as stable. Unfortunately, the torture test failed within 2 minutes. I tried again and the same result. I was a little discouraged at that point , but I decided to give the processor more juice (voltage) and see if it’ll work. I went back into the BIOS and increased the voltage to 1.725 volts. According to many sources, Athlon XPs should not have a voltage over 1.75volts, so this is just barely under that. I went into Windows again and tested. This was the moment of truth. If Prime95 fails quickly, then I was going to give up overclocking this processor. Fortunately, this time it didn’t fail, which means that my computer works at 2.2ghz. Great!

After achieveing 2.2ghz, I tried to push the cpu a little further. I changed the FSB to 205Mhz, but this setting would fail the test really quickly. I upped the voltage to 1.75, but it didn’t help, so I guess 2.2ghz is as far as the cpu and the memory of this system will go in the current setup. This is a 20% overclock, which is considered to be moderate by most enthusiasts, but I feel that it is no small accomplishment, especially for a newbie like me. Here’s a picture of a diagnostic program identifying my cpu.

CPU-Z (the name of the program) identifies my processor now as a XP3200+, because other than the voltage, my processor and a 3200+ are indentical. You might also have noted that in the voltage box, the program doesn’t show 1.725 volts as I have stated. This is because the voltage set in BIOS is not exactly the same voltage that actually goes to the cpu. When at stock, the voltage in CPU-Z reads 1.616 volts.

It’s now time to check the temperatures, since the reason why I backed off the first time is because of temperatures near the 60s. Below is a chart for comparison. All the readings are in degrees Celsius and is the temperature of the diode inside of the cpu itself.

As you can see, the temperatures with the new Silent Boost heatsink is much better than when I used the stock heatsink. As expected, the temperatures all rose somewhat. 50 degrees Celsius is still kind of high, but remember that Prime95 uses 100% of the cpu cycles, so in everyday situations, that is unlikely to happen. These temperature may increase during the summer since room temperature will be higher, but hopefully they’ll remain within 55 degrees.

So what does this increased processor speed mean. I have ran some benchmarks before and you can see them on this web page. I also ran PCMark 2004, a benchmarks which tests a computer’s over performance by doing such tasks like file compression and music encoding. Here are the results:

My computer at default: 2991
My computer overclocked (both CPU and video card): 3436
My mom’s Compaq with 2.5Ghz Celeron (for comparison’s sake): 2131

Other than overclocking my processor, I also decided to tweak the timing of my memory a little bit. I don’t think my current setup will allow me to crank the FSB up any more, and I doubt that I will shell out the dollars for top quality memory, so I looked for another way to increase performance. Memory timings are the time periods the memory has to take to complete one operation. I’m a complete newbie at tweaking memory so I don’t know what the timings really mean, but I do know that in general, lower timing will result in better performance, but less overclockability and maybe less stability. The purpose of tweaking timings is the same as with overclocking: to squeeze out every bit of performance out of the system.

Anyways, to tweak timings, I had to restart my computer and go into the system BIOS again. My motherboard offer the settings to change memory timings, so I went into the appropriate menu and changed some values. Memory timings have four values and are usually listed like this: 2-3-3-8. Again, I’m not sure what each value means, but they are listed in the order of importance. For DDR, the first value is either 2, 2.5, or 3. The second and third values are 2, 3 or 4. The last value are integers ranging from 5 to 11 or more. The default specs for my generic Samsung memory are 2.5-3-3-8 at DDR400. These are okay timings. They are by no means “tight” but they aren’t those very “lose” as experts call them. I searched around on the internet and found people who could get even these generic stuff down to like 2-3-3-6, which are pretty good timings for generic memory. Of course, specialy designed low latency memory can run at 2-2-2-5, but 2-3-3-6 are pretty good for a 512MB stick that costs less than $80 Cdn. I also found out that for my motherboard chipset, the Nvidia nForce2, memory performance is actually better if the last value is set to 11. I don’t know why it is this way but I’ll heed to this advice anyways. So sticking to my “research,” I set the timings to 2-3-3-11, and then rebooted. Everything seemed to be fine. I got into Windows and nothing crashed for no apparent reason, so I fired up Prime95 for some torture testing. No problem. I turned on CPU-Z to look at my timings, and here they are.

As you can see, CPU-Z correctly identified my memory timings. Diagnostics don’t really mean much, so lets run some benchmarks.

Sisoft Sandra Memory before at DDR400: 2846/2670 After: 2869/2695

So that there is a teeny tiny little improvement on bandwidth. Lets see if gaming fares better or worse.

3DMark2001SE Before: 10244 After: 10533

Well, in this case the increase slightly more noticeable, but only a small percentage nontheless. I wasn’t expecting a whole lot since all the articles I’ve read told me that tweaking timings wouldn’t bring drastic changes in performance. My memory is also generic stuff, so that’s about as fast these things can go. These timings seem stable though, and they do provide slightly faster performance, so I will probably keep them. Oh, you might have noticed the difference between the two CPU-Z pictures. That’s because the memory tweaking is an update to this article and I applied some customization program to the Windows interface, so it’s all black and cool now. It’s still the same computer though.

In the end, overclocking my computer basically means applications will be a little faster and there will be a few extra frames per second in 3D games. Nowadays, an Athlon XP at 2.2ghz can be bested by even the lowliest of Athlon 64s (the 2800+ at 1.8Ghz) and any 800FSB Pentium 4s over 3Ghz, so my rig is still not a real performance champ, but I’m satisfied with its performance and this experience, since nothing bad has happened (yet). I don’t play any new games and besides, my graphic card probably can’t keep up. I’ll keep my processor at 2.2Ghz from now on and enjoy the power of a 3200+ for the price of a 2500+.