Overclocking Basics and Temperature Guide

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Kangaroo

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Basic guide to overclocking

To overclock you must have adequate cooling.

Getting higher performance, also very free performance, out of your current CPU can be done by overclocking - overclocking is dangerous and should only be attempted in small incremental steps/stages.

Overclocking voids hardware warranty, can damage hardware or can make a system unstable.

First you look at your temperature, for most modern CPU's if your temperature is around 30 - 40 degrees when idle it will increase to 37 - 46 under a heavier load. I personally wouldn't overclock if my CPU doesn't fit within these boundaries, my XP2500+ has a temperature that is too high and thus I don't overclock.

Overclocking will reduce the lifespan of your hardware, but seeing as though hardware lifespan is something as rediculous as 1,000,000 hours, whats the harm in taking a few thousand from that? :D

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Down to it.

Overclocking can be done in 2 main ways.
Firstly raising the FSB speed by a few MHz and letting the multiplier do its job.

Example, say you have a AMD Athlon XP3200+ (2.2GHz) with a FSB speed of originally 200MHz (in BIOS) and a multiplier at 11, giving a total GHz of 2.2, 11 x 200MHz = 2200MHz (2.2GHz) .

Increasing this FSB speed to 205MHz BIOS will give you:

205MHz x multiplier of 11 = 2255MHz (2.26GHz)

Simple see! A problem you might encounter is that your system becomes unstable, to make the CPU stable again you should give it more power, i.e. increase the voltage, from 1.65V (default for the XP3200+) to 1.675V or maybe 1.7V.

Increasing the voltage substantially increases the temperature depending on what cooling solution you have.

Repeat these steps until you have a satisfactory speed and temperature, and hopefully a stable system.

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It is simple to correct the problem when Windows won't boot because you have overclocked too far; you can obviously step the MHz down a little bit until it does boot. The reason I say 5MHz is because some people have multipliers of 9 and others 13, i.e. giving a total overclock of 5MHz x 9 or 13= 45MHz or 65MHz - there is a substantial difference see

The bigger problem, and one I came across recently, is when BIOS won't even boot - you get the black screen of death.

It is simple to reset BIOS, so keep a note of how far you have overclocked because you might have to reset BIOS to default.

Clearing BIOS

This may vary from system to system, please refer to manual.
This is based on the Asus A7N8X-E-Deluxe motherboard

Clear RTC RAM (CLRTC1)
This jumper clears the Real Time Clock (RTC) RAM of date, time and system setup parameters in CMOS. The RAM data in CMOS is powered by the onboard button cell battery.

To erase the RTC RAM:
1. Turn OFF the computer and unplug the power cord.
2. Remove the battery.
3. Move the jumper caps from pins 1-2 (default) to pins 2-3, keep the cap on pins 2-3 for about 5-10 seconds, then move the cap back to pins 1-2.
4. Install battery.
5. Plug in the power cord and turn ON the computer.
6. Hold down the <Del> key during boot to enter BIOS and re-enter data, i.e. the Date and Time.

This isn't dangerous, I have done it several times and it has worked every time - very simple!.

The pins referred to in these steps is found right next to the battery, but this will probably vary from motherboard to motherboard.

Intel or AMD?

Temperature

I have heard lots of responses to the question "which runs hotter, Intel or AMD?", but the truth is, it depends on the model of your CPU, the quality of cooling, or the ambient room temperature.

Intel have a lower temperature threshold so that would suggest that their CPU's run at a lower temperature, they are hardly going to have operation temperature and maximum temperature too close together, because that is just waiting for disaster.

Intel run cooler but their maximum temperature is lower, AMD run at higher temperatures but their maximum temperature is higher. This can be seen here:

cpu_history_big.gif


Overclocking

AMD fans will be devastated to hear that it is Intel which have the highest overclockability, their pipelines and architecture is a lot larger and is able to handle insane frequencies - but AMD are better for Doom 3 :p

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If you are wondering "What does this guy know about overclocking? None of his hardware is overclocked.", but it is true that I do overclock occasionally. My hardware remains in the state I bought it because the temperature varies so much in my 2 rooms that I would have to be monitoring the temperature constantly to ensure I don't damage my CPU/GPU/Memory.
 
Overclocking your memory.

A lot of memory doesn't like being overclocked, but if you buy more expensive RAM like Corsair, Kingston, OCZ or Mushkin you can have a little bit of fun.

These makes of memory (excluding Kingston ValueRAM) are made with high quality chips, don't hesitate to send memory back if you have found faults with it using memtest86.

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You can get higher performance out of your memory by doing two things, increasing the MHz or by lowering the CAS latency. Either is fairly easy but you should be just as careful when overclocking memory as you are when overclocking CPU or VGA.

Overclocking memory is most effective within BIOS, therefore get ur ass out of Windows and back to old skool BIOS and simple GUI.

You must increase your FSB (overclock CPU) as well as increasing your memory or it is pointless. There is no point having a memory speed of DDR450 if your FSB only accesses it at a speed of 400MHz. By increasing the MHz of the memory your CAS latency will increase also, you should try and avoid this best as possible.

Increasing the MHz of the memory within BIOS is the same as FSB speed, mathematically that is, i.e. 200MHz in BIOS will give you DDR400 or PC3200 (DDR400 x 8 for bits); so be careful when overclocking, 5MHz is really DDR10 or 10MHz is really DDR20 (simple see!).

If you don't want to increase your FSB but want faster memory you can fiddle about with the CAS latency settings, i.e. my Corsair is 2.5-3-3-6 (it is now, 2 for Intel).

timings.gif


The active precharge at a higher latency can sometimes improve performance depending on which chipset you have.

To make the memory stable you must increase the voltage just as you did during overclocking your CPU.
 
Overclocking VGA is easier, and can be done within Windows.

For overclocking your ATI graphics card I would recommend Rage 3D Tweak utility:

Article

Download here!

For all you boys and girls with NVIDIA cards there are two options depending on how old your card is. NVIDIA were kind enough to include software with their drivers... but they were also cruel enough to hide them from us. The simple proceedure to reveal this hidden overclocking utility is to download and install this program, I will let you read about it first of course:

overclockers.com

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In either case you should only overclock your graphics card in small increments of 5MHz and running benchmarks. The range of your overclocking ability obviously depends on your card manufacturer and model, and the ambient temperature of your room/inside case. To get a rough idea of how high you can overclock your graphics card you should read reviews, use the data only as guidelines.

PC Stats
Tomshardware
Hexus

To test whether your new settings are stable or not you need to benchmark. Benchmarking is a way of testing all the features you card offers, individually and combined - latest features for X800 XT and 6800 Ultra:

ATINVIDIA
Wow that was a lot of editing!

The Benchmarks I use for testing to see if my card is stable are:
3DMarks 2001SE (b330) and 3DMarks 2003 (b340) from Futuremark.

And Aquamark 3 from BADCT

The problems are pretty easy to see, just look for glitches, sudden closes of the application or errors. If you find you are getting errors then just step the MHz down until you get none - please be aware that heat effects VGA cards over time and higher load, so if you run just one benchmark your card hasn't even warmed up, make sure you run it twice without errors before increasing the MHz - give the card heavy load over time to see its reaction.

[size=3.5]Finally got a couple references, will add more as time goes on - any requests are welcome.[/size]

GeForce 6800 GT has a default core clock speed of 350MHz and a memory clock speed at 500MHz (1GHz DDR). For the PNY manufacturer of the GeForce 6800 GT it was overclocked to a comfortable 375MHz core speed and 550MHz memory speed (1.1GHz DDR).

The GeForce 6800 Ultra with default speeds of 450MHz and 1.1GHz (DDR3 technology). The XFX version was overclocked to 473MHz and 1.2GHz, it was stable enough to run every test hexus.net could throw at it.

ATI X800 XT Platinum with default speeds of 520MHz GPU and 1120MHz memory (DDR3). ATI X800 Pro has stock speeds at 475MHz core, and 900MHz (DDR3) memory - hopefully find their overclockability soon.

Asus ATI 9600XT Default = Core 500MHz (higher than usual 9600XT models), memory 300MHz (600MHz DDR), PCstats.com got it upto 553MHz and 341MHz (682MHz DDR).

Hope this helps some of you.
 
[size=3.5]What are the benefits of PCI-Express x16?[/size]

There are lots of new technology coming out at the moment, and one of these is PCI-Express x16 - massive bandwidth and everyone happy that it is backwards compatible with old PCI cards.

There are 2 reasons why high-end cards aren't on PCI-Express at the moment, these being:

The benefits first, and why are there no GeForce 6800 Ultra's or X800 XT's in a PCI-Express format?

Bandwidth
PCI Express design provides more than double the bandwidth of AGP solutions. Full bandwidth is available in both upstream and downstream directions simultaneously, whereas AGP is only capable of unidirectional bandwidth.

Power Management
The serial bus with the reduced pin structure of the ATI native PCI Express architecture reduces the number of signals required, supporting lower power consumption and PCI Express's low-power idle states.
Notebook users will find this feature of particular importance.

Company experience second, large companies know that only about 10% of their sales are high-end graphics cards, now compare this to how many people currently have PCI-Express x16 (2%? If that), their high-performance graphics cards on AGP only sell at a minimum, so imagine the sales of high-end cards on PCI-Express.

PCI-Express Architecture
 
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