Overclocking Guide by Sin22
Ok, to get started, you’ve received your nice little bombshell of a computer and you see its an AMD chip and you’ve heard so much about overclocking that you want to try your hand at it. But wait, you’ve never done it before, so what do u do….come online and search for sites on overclocking.
Remember this, overclocking your Front Side Bus (FSB) generates MORE heat and stresses your components out.
Furthermore, AMD does not uphold its warranties when chips come back scorched due to overclocking experiments gone awry.
Do remember that overclocking is a dangerous thing to do, albeit fun. Once you’ve started overclocking, you can’t stop.
I believe it would benefit greatly from stating straight off here and now that whatever mishaps happen with your overclocking , that it still cannot be taken back scorched and damaged. This is a notice to all n00bs(people without much experience in computers) to NOT go crying to me, or the Admin begging for them to return u a brand new working Athlon once you’ve FUBARed yours. So please keep that in mind. (i.e. this is a disclaimer!)
Now onto the fun part. Overclocking can be broken down into two main streams. Normal overclocking and extreme.
Normal easy Overclocking
Normal overclocking would involve changing your FSB of your chip to something higher than its default FSB (100mhz for Durons, 133mhz for Athlons and most AthlonXPs and 166mhz for some AthlonXPs) and thus make it run faster than its supposedly rated for.
You are normally limited by your motherboard to how high you can change your FSB to and other things hold you back, dodgy ram, other dodgy PCI cards. You see, when you increase your FSB, you are also increasing the speed of ALL the equipment on your mobo, this does stress them out but for minor overclocks this aint nothing, and pls, half the time people upgrade in 1-2 years anyhow. So you hit maybe 140fsb, are happy with your overclock and leave it be.
The other aspect would be to just change the multiplier on your CPU for AMD CPUs. This is easily done in the BIOS of most good motherboards. All CPUs work on the principle of the FSB multiplied by a preset multiplier to obtain the final clockspeed. i.e. 133MHz x 10 = 1.33GHz. Intel CPUs unfortunately have their multiplier hardlocked, AMD CPUs do not suffer this fate. With the recent releases of Thoroughbred and Barton cored AthlonXPs, all the CPUs multipliers are default unlocked. However, the Thoroughbred A and earlier Palomino and venerable Thunderbird cores do require you to unlock the multipliers. This is easily explained in the next section.
|For Athlon ThunderBirds (T-Birds) its a simple procedure thats why I am putting it under just normal easy overclocking and not under extreme overclocking where multiplier unlocking normally is. All that is required is to connect the L1 contacts on the chips surface which can be found on the top left hand corner of the chip. Connect the two rows together using a HD or 2B pencil
(where u had :::: , now u have ||||)
and u’re done. This unlocks the multiplier.
Physically modifying your chip for Athlon XPs and the old Athlon K7(Slot As) is quite a daunting task, but something most people will pursue for those extra MHz. For Athlon XPs it involves connecting the L1 multipliers so as to unlock the factory set multipliers on the chip. The tried and true method which MOST people use involves Silver laquer and superglue, physically connecting the two bridges with the conductive silver lacquer.(A guide to do this is found on Tom’s Hardware Guide under GUIDES). Once this is done, your chip is unlocked.
I’ve done a pictorial guide as well which can be found here. Mind u, its only for Thoroughbred cores.
The AthlonXP Thoroughbred cores these days are coming unlocked and a lot of motherboards can actually unlock them automatically in the BIOS some cant though, so check up first before purchasing a board.
Multiplier & FSB overclocking
This is the fun part to me. You chuck it in, make sure it works and start playing around with the multiplier and FSB. Hopefully u have a motherboard with a good FSB range (something along the lines of 100mhz – 250mhz with 1mhz increments) The best thing would be to drop your multiplier to something like 9 and increase the FSB slowly and see how high it can go (this example is for Palomino cores), once your system doesn?t post, you know its too high so drop it back down. Then if WinXP doesn?t post drop it down more, then run 3DMark2001 on a loop, perhaps 10 runs and everything is generally fine and good, you’ve got a stable overclock…however if it crashes, drop your FSB some more. This isn?t the only program I’d recommend u run, I’d suggest running Prime95, SuperPI or HotCPU Tester to further test stability.
Voltage & PCI frequency explained
Also when increasing your FSB, once u hit the CPU?s limit for that level, increase the voltage supplied to the core and then try increasing your FSB some more. Keep on doing this till a Vcore of about 1.9V…highest voltage I would really recommend on aircooling, anything higher u would need a good cooling solution like water cooling and its a tad more difficult. The good thing with the newer motherboards which use the VIA KT333 chipset onwards is the 1/5 PCI Divider. This is there to ensure that your PCI/AGP bus works at its default specs of 33.3/66.6MHz respectively. It only kicks in after 166mhz. This is good that way all your PCI devices will benefit from the increased bus speeds and yet will not conk out due to extremely high and out of spec bus speeds. how it works is it takes your current FSB and divides it by the multiplier. So at 200mhz, your PCI bus is working at 40Mhz. KT600 has implemented a 1/6 PCI divider for use. OR u can go for an nForce2 option which has locked PCI/AGP freqs.
Voltage is generally your friend, remember tat. More voltage translates into better stability and higher overclocks BUT it comes at a price, higher operating temperatures. This goes for memory overclocks as well. Many boards have a limit of 1.85V as your max VCore, this can be overcome with a simple Volt mod, this mod varies on different boards so check up on info for your own particular board. Basically, its tricking the controller into thinking the CPU requires more voltage. More boards these days actually have options to allow Vcores above and beyond 2.1Vs.
Old Style Overclocking
For the older Athlon K7s, u could do it two ways, either using a Gold Finger Device which utilised either crocodile clips to clip onto the chip or u could solder some of the contacts closed…I wont go into this in much detail as these chips are rarely seen these days.
For the even older and venerable K6-2 chips. Overclocking was done by dipswitches or “short” switches on the motherboards themselves. You’d have to find the right combination to overclock your CPU.
To get some really good clocks and if you are not too worried about performance, make sure that your ram is set to its default timings…so no aggressive timings. This will help in boosting how high an overclock u can get. With aggressive timings u will find that your overclocks wont be as high, when its based on FSB adjustments because you will be overclocking the RAM speed as well. 100MHz FSB translates to 200MHz DDR RAM bus speed. That obviously equates to certain limitations of an overclock based on the type of RAM you have.
What needs to be stated is that when overclocking, you need good heat dissipation. So that means a good HSF(Heat Sink Fan) and also a good cooling rig. Clear out the clutter caused by ribbons IDEs and get rounded ones, use cable ties to tidy up and also install some case fans with the prime objective of getting air flow going through your case and over your hot components.
||A good cheap HSF is the Coolermaster Aero7+. For more expensive ones, there is the Swiftech MCX462+ and the Thermalright SLK800 which would be another two I would suggest. The best is at the moment the Thermalright SLK-900. These are all good aircoolers.|
You could add an airshaft, wind tunnel, or other air channeling modifications to your case, but I wont go into it here as those are more in the Case Mods section…they do help with the cooling down of your CPU, but I have not had much experience with them. Results vary as well to some with really significant cooling properties to others with mediocre ones.
However, if you’ve really been bitten by the overclocking bug, then the next and only step to go in cooling would be watercooling. This I must state is considered slightly dangerous…putting water and expensive electronic equipment close together is not always the easiest of ideas to get used too, so dun skimp. You’ll need a minimum of $200-$250 for a decent water cooling setup. Awesome ones can run into about $600. But the benefits are there, you’ll be able to squeeze out those FSBs for sure. One great thing about watercooling is the plethora of methods to setup a watercooling rig. There are a few set methods. A closed inline loop or running with a reservoir. And there are variations on these two as such they will be discussed in another article.
The next step up would be Peltier cooling, or Thermal Electric Cooling (TEC). This uses a peltier hot plate with the cold side on the CPU core and the hotside on the base of the waterblock and now some heatsinks to cool the CPU down to below or near ambient temperatures. Condensation and malfunctions are quite a worry with TEC cooling. So think carefully before going into it.
The final step in most circles would be to try out phase-change cooling. Put simply, it is a refrigerator in your computer. Same principles to some degree as watercooling, but better results as the CPU runs even cooler. Vapochill and Prometia are the only two commercial companies that offer such compact systems.
Last but not least, would be dry ice, liquid helium and liquid nitrogen cooling, that is if u can source them out. This is only if u have a great burning desire to see your chip hit as high as possible a clock. These methods of cooling do not, repeat DO NOT allow for sustained day to day usage of the computer unless serious financial resources are commited.
nForce2 overclocking update
Well there have been some changes in the overclocking realm now with the introduction of the nForce2 chipset from nVidia.
I didnt update this guide for the KT400 chipset cause it really didnt bring anything new to the table overclocking wise. It really was just a slightly more integrated version of the KT333.
The main differences can be summarised as follows:
1)Official support for DDR400 SDRAM with Dual Channel DDR capabilities
2)Locked PCI and AGP buses on certain motherboards. Epox 8RDA+, Abit NF7, ASUS A7N8X
3)Hotter Northbridges & Southbridges
With official support for DDR400, and also allowing for Dual Channel DDR which IMHO is a marketing gimmick as I’d stated before and so learnt myself, the nForce2 chipset when run with a synchronous FSB of 200mhz flies, coming close to and surpassing what Intel has to offer on many an occasion.
But the key thing is running the FSB synchronously and at FSBs of 200mhz or more. That is another impressive thing, the nForce2 chipset has seen boards running at 238mhz FSB, a previously unheard of phenomenon on normal KT333 boards.
What this leads into is the fact that good ram is required. Winbond BH5/6 chips are still sought after and seen as the de facto overclocking ram modules used by Corsair and many an avid overclocker.
|Next up is a board that can do 200mhz or more. The Epox 8RDA+, ASUS A7N8X, Abit NF7, MSI K7N2 and the Soltek SL75FRN have all been “known” to hit those high FSBs. HOWEVER, the ones which are generally used to attain steady 200mhz+ overclocks are the 8RDA, NF7 Rev1.2&2.0, A7N8X.
The inclusion of the PCI and AGP lock aides greatly in overclocking, whereby you dont have to worry about PCI dividers and what sort of detrimental effects that they may have on your modems, or HDDs. Thats one reason why the barrier of over 200mhz FSBs has been broken.
One draw back of the nForce2 chipset though is that the northbridge and southbridge now are a lot hotter than they used to be, and manufacturers are more skimpy than ever, with many a board featuring a passive HSF. The solution on the A7N8X is good, using a Zalman ZM-NB32J look-alike heatsink, the NF7 uses a small 40mm fan to cool the NB but the Epox uses a piece of designer crap aluminum that they label a heatsink. Change that ASAP. The southbridge gets fairly warm too and without proper cooling, can lead to scratches in the sound quality of the onboard sound. A simple ex-NB heatsink will solve the problem of heat on the SB. Definitely look into active cooling for the NB if u are looking at loftier goals.
One piece of warning, the nForce2 does suffer from a weak BIOS problem. Whenever u are playing around in the BIOS, as in doing any changes besides FSB changes, make sure u do them at STOCK frequencies and not overclocked frequencies. This is especially true for the Abit NF7 and Epox 8RDA. These BIOSes seem to be too feature rich and as such when writing all the code into the flash memory, they tend to sometimes coz a traffic jam, to put it simply. And u might end up with a dead ROM. A solution has been to try rebooting with the INS key depressed and a floppy with a BIOS image inserted.
With that said, good look and all the best in your overclocking adventures with the latest and greatest AMD chipset
Contributed by Sin22
15 August 2003