From Extreme Overclocking

Contents 1 The Available CPU's 2 The Technicalities 2.1 Interpreting Codes 2.2 Core specifics 2.2.1 Socket 754: 2.2.2 Socket 939: 2.2.3 DUAL CORE 939 2.2.4 Socket AM2 3 Overclocking 3.1 Knowledge you need 3.2 Basic overclocking 3.3 Tweaking on... 4 FAQ for Newbs 5 Useful Links 5.1 CPU's 5.2 Memory 5.3 General

The Available CPU's

Only CPU's that are somewhat modern are in this list, otherwise it would just become uselessly large.

LEGEND:

Terms:

• Socket: No, you may not mix these numbers up...
• 754 = Home of: Sempron, Athlon64. Single Channel
• 939 = Home of: Sempron, Athlon64, AthlonFX. Dual Channel
• SC = Single Channel ram controller
• DC = Dual Channel ram controller
• Ram controllers are integrated in the 64 chips, the mobo manufacturers have no influence on it anymore...

• Light green: The mass

• Light blue: The CPU you'll want to look at

The Technicalities

Interpreting Codes

At the end of the CPU number there will be a code, first a number and then two letters, they can be translated like this:

The OPN-suffix will tell you the type/revision of the core, you can find it at the VERY end of the first line in the CPU code:

• AP - Clawhammer, rev. C0 (avoid this!)
• AR - Clawhammer, rev. CG
• AX - Newcastle, rev. CG (ALL Newcastles are rev CG)
• AW - Newcastle 939
• BI - Winchester
• BP - Venice
• BN - San Diego
• BV - Manchester
• CD - Toledo
• BOX - The CPU is a boxed version, this means you get the heatsink as well.
• When this code starts with an A it is a 130nm CPU, if it starts with a B, it is a 90nm CPU.

The number before this code represents the amount of cache:

• 2 - 128KB (Sempron)
• 3 - 256KB (Sempron)
• 4 - 512KB (Newcastle, Winchester, Clawhammer may have it when its turned down for a Clawhammer, it's then clocked at the NewCastle speeds...)
• 5 - 1MB (Clawhammer, San Diego)

For the dual cores count is different, as in -1, for whatever reason. That means that 5 means 512KB cache, and 6 are the 1MB versions.

Examples:

• ADA3000DAA4BP - The Athlon64 90nm Venice 3000+, 512KB Cache.
• ADA3700BNBOX - The Athlon64 90nm San Diego 3700+, Boxed.
• ADA4800AA6CD - The dual core 90nm 1MB 4800+.

Core specifics

Here's where I'm gonna list the specifications per core, and their OCability.

Socket 754:

Clawhammer Specs: 1MB Lvl2 Cache, multiplier is one lower than the Newcastle variety of the same rating.

Ups and Downs:

• + 1MB Cache
• + Overclocks nicely if you get a CG revision
• - Lower multiplier
• - You're gonna wish you'd gotten a NewCastle when you get C0, they have horrific memory controllers to our standards.
• - It may be a bad Clawhammer, in that case you've gotten one with only 512KB cache and the NewCaslte multiplier. Don't think it'll OC like a Newcastle however, because it won't. If you get one like this, you have the worst of both sides.
• - Single Channel memory controller

Newcastle Specs: 512KB Lvl2 Cache, multiplier is one higher than the Clawhammer variety of the same rating

Ups and Downs:

• + Guarantueed of a CG revision, meaning they all OC pretty nicely
• + Less cache = less Vcore required = less heat = even better OC
• + The multiplier, get yourself a 3200+ and you've got plenty of multi to play with, so that you don't need uber ram or a major HTT divide to get high clockspeeds
• - Only 512KB Lvl2 Cache
• - Single Channel memory controller

Socket 939:

Newcastle 939 Specs: 512KB Lvl2 Cache, multi equal to Sct 754 version.

Ups and Downs:

• + Guarantueed of a CG revision, meaning they all OC pretty nicely
• + Less cache = less Vcore required = less heat = even better OC
• + Dual Channel memory controller
• + The multiplier
• - Only 512KB Lvl2 Cache
• - Aged

Clawhammer 939 Specs: 1MB Lvl2 Cache, multiplier is unlocked for the FX chips

Ups and Downs:

• + Unlocked multiplier*
• + 1MB Lvl2 Cache
• + Dual Channel memory controller
• - The price
• - Aged

Winchester Specs: 512KB Lvl2 Cache, Multiplier is 1 lower than the newcaslte variety (3200 Winchester = 3000 newcastle 754)

Ups and Downs:

• + 90nm
• + OCes like mad
• + Dual Channel memory controller
• + The price (lower than expected)
• - Only 512KB cache
• - There's a chance you get a bad one
• - A bit aged

Venice Specs: 512KB Lvl2 Cache, Multiplier is equal to Winchester version.

Ups and Downs:

• + 90nm
• + Strained Silicon
• + New and improved E.rev/Mem controller
• + Dual Channel memory controller
• + OC's insanely
• - Only 512KB cache

San Diego Specs: 1MB Lvl2 Cache, multiplier is unlocked only for FX!

Ups and Downs:

• + 90nm
• + Unlocked multiplier*
• + 1MB Lvl2 Cache
• + Dual Channel memory controller
• - Price

Venus Specs: 1MB Lvl2 Cache, Opteron rating system

Ups and Downs:

• + 90nm
• + Opteron core
• + 1MB Lvl2 Cache
• + Dual Channel memory controller
• + Cheap for its performance
• - Multiplier restricted on not so good overclocking motherboards
• - Single Core

DUAL CORE 939

• Common advantage: Very good multitaskers due to 2 physical CPU's on the chip, and they are 90nm

Manchester Specs: 2x512KB Lvl2 Cache

Ups and Downs:

• + Relatively Cheap
• - Small cache for DC

Toledo Specs: 2x1MB Lvl2 Cache; Home of the FX-60, worlds fastest consumer CPU!

Ups and Downs:

• + Very powerful core(s)
• - Rather pricey (especially the FX of course)

Denmark Specs: 2x1MB Lvl2 Cache; Opteron version of Toledo

Ups and Downs:

• + Very powerful
• + A little cheaper than Toledo, but similar or better performance
• - A little pricey still

Socket AM2

Orleans Athlon 64, single core

Ups and Downs:

• +90nm
• +62W max tdp
• +Very Cheap
• +Good Overclocker
• -512kb of L2 cache, 90nm
• -Single Core

Manila Sempron, single core

Ups and Downs:

• +90nm
• +62W max tdp
• +Very cheap
• +Good upgrade path to high end AMD processors
• +Good Overclocker
• -Only 128kb or 256kb of L2 Cache
• -Single Core
• -A full AM2 A64 is almost the same price

Windsor Athlon X2, dual core

Ups and Downs:

• +90nm
• +Dual Core
• +Cheap
• +Good overclocker
• +2x 512kb or 2x 1mb of L2 Cache
• -Out performed by Core 2 Duo

Brisbane Athlon X2, dual core, 65nm

Ups and Downs:

• +65nm
• +Dual Core
• +65W TDP
• -Outperformed by Core 2 Duo
• -Very Limited Availability

Overclocking

Knowledge you need

• CPU

The center of any computer, this in the chip that makes it all possible. The Central Processing Unit gets all the commands in the entire computer, tells the other parts when they need to know so they can perform their task. Of course this is an extremely heavy task which takes a huge potential. What makes it possible is a frequency generated by a crystal on the Motherboard (MoBo), which is then turned into a very high clockpulse, which runs through the CPU at a set voltage. You can adjust all these values at the risk of overloading your CPU, in human language: “blowing it up”. Modern CPU’s are so fast that some people say they need no adaption to make them handle tasks better. Us overclockers disagree.

• Overclocking itself

Simply said, upping the frequency that runs through the CPU. This involves more than meets the eye, as you will find out reading this guide. There are many variables you have to take in to account, make certain parts even run slower than they can, only so you can allow another part to run significantly faster than stock, resulting in a higher end speed nonetheless. Please remember, and don’t say that I didn’t warn you (don’t have the nerve to contact me and ask ME for a refund for your CPU), overclocking WILL destroy your parst in the long term, and it WILL void your warranty. Die hards usually don’t care, “it’ll die sooner or later anyway”. This is entirely true. But if you don’t have money to burn you might not want to just destroy a CPU. Personally I don’t care if a CPU blows, it’s a good excuse for an upgrade. Generally CPU’s under my control are happy to reach their first anniversary because the voltages I use are crazy, even though my parts are water cooled. I also warn you beforehand that if you try to RMA your CPU to AMD because your blew it up while overclocking, the chances of a refund are MINIMAL.

• The memory controller

As most people know by now the Athlon 64’s have an integrated memory controller. This means that RAM latencies are drastically reduced. While an Athlon XP and a Pentium 4 (P4) have an external memory controller, which is located in the so called “Northbridge” (NB) of the motherboards, with the Athlon 64 it is so called “on die”. That means it is literally on the CPU, as a part of it. This rules out the delays the XP and P4 have, which have to communicate with the NB. The P4 and XP get a memory latency of approximately 130-140ns, while the 64 only has to wait for about 60-70ns. Both may sound like they can be forgotten about, but the advantage of having half the memory latency is very significant, IF you know how to use it properly. If you read this guide well you will be able to do just that.

• The HTT

The HTT (Hyper Transport Technology) is the technology the A64 uses to communicate with the RAM, and the Chipset(s). It’s very hard to explain, but I’ll try anyway. When people are talking about the HTT they can mean two things.

• 1. The actual HTT. This is the link between the CPU and the Chipset/RAM. Depending on the socket this will run at either 600 (nForce3 150), 800 (nForce3 250/GB, VIA K8T800) or 1000 (nForce3 Ultra, nForce4 Pro/Ultra/SLI, VIA K8T800 pro) Mhz. Of course, the faster, the better (not entirely, but we will get to that later).

• 2. The “base frequency” HTT. Stock this is 200Mhz on every 64, so far. In the near future we will see 267Mhz as well. This is the frequency you are actually changing when you want to overclock. This is also the value we will be talking about when overclocking. When someone says he has a 64 at 230 x 11, he means he has set the “base frequency” to 230Mhz, and is running an 11x multiplier. Obviously that means he is running his CPU at 2530Mhz. The base frequency x the HTT Multiplier = the actual HTT.

When overclocking this value you’ll run into all kinds of problems, which we’ll discuss later.

• Multiplier

This is the value you will multiply your base frequency with to get your CPU's actual clockspeed as a result. When OCing you can drop this to get more bandwidth on your ram (if you have to divide your ram to be able to up your HTT, it's no use to lower your multiplier and do this). Never use .5 multipliers, you'll lose ram performance (complicated, don't ask why).

• Ram dividing

Unlike in Athlon XP and Pentium 4 systems, Athlon 64 take absolutely NO performance hit when using a memory divider, so don’t be afraid to divide that memory when you hit a wall with your ram.

[The real speed of an A64 speed is the clock of the CPU, every other value is derived from this. So if your CPU runs at 2200Mhz (11x multiplier) the bios devides the CPU clock by the multi (2200/11) and you have the ram speed. This means that the ram on an A64 is ALWAYS divided. So placing it under (for example) a 200:166 divider means you “slow down” the ram a bit more. But now if you speed up the HTT so that your ram is running at 200Mhz again, your CPU will be overclocked. And pretty much the only thing you did was change your multiplier up. To about 13.2 to be exact, if you’re a fanatic you can try to recalculate that]

• RAM Timings

These are the delays your ram takes, measured in clock pulses. The lower these numbers are, the better. We usually use 5 values in the following order: Cas-RasCasDelay-RowPrecharge-RAS-CommandPerClock, you’ll find them in your BIOS. If the fifth number is missing that’s not a big deal, but in your own rig ALWAYS keep this set to “1T”. This results in to about 20Mhz more memory performance as opposed to 2T. High timings are lethal for any A64’s performance. Because of the integrated memory controller they’ve got a RAM advantage, and this would even it out. Not so nice.

• RAM voltage (Vdimm)

The voltage you are giving your ram, typically anywhere from 2.5 to 3.0V. People that go over that are either insane or know what they’re doing, which comes down to the same thing.

• SPD

Serial Presence Detect, these are the factory recommended settings you put your RAM at so that it runs fine at a certain amount of Mhz. My advice: Ignore it. Manually giving in the timings usually results in a faster system in the end.

• Vcore

The voltage you are feeding your CPU. For the Athlon64 this can (for stock values) vary from 1.35 to 1.55V. When overclocking you will meet instability, and this is a value you might then want to increase. You always have to be very aware of the temperatures though, because Vcore is the main reason your chip even warms up in the first place. Without it it won’t work, compromises, compromises. When do you need to up your Vcore? When you get something like this:

• 1. BSOD: Blue Screen Of Death. Ask any overclocker, he’s seen it. And some people that don’t OC get it too. This is typically what you get when you overclock too far on too little Vcore, its Windows’s way of telling you you screwed up. It is literally a blue screen, with white text explaining what’s gone wrong. Don’t mind the bottom bit, that code is useless to us though the information on the top can be useful.

• 2. No Boot: Your CPU turns on, but it craps out (jams, or automatically reboots) during the boot up. Your Vcore is again too low.

• 3. No Post: You screwed up bad. Now you have to reset CMOS, no matter how you do it, by holding insert or delete during boot up (only some mobo’s support this) or by using the mobo’s jumper/removing the battery, you have to do it. This resets ALL you settings, so it sucks if you’ve forgotten what and whatnot your changed in there.

The solution to all of these problems is to up the Vcore. But if temperatures do not allow for this (max for 130nm: 55, 90nm: 50ºc) it’s the end of the line and you’ll have to easy back on your overclock.

• CMOS

This is the chip the BIOS uses to store its settings, if you have to reset it all settings will be back at stock.

• BIOS

Basic Input Output System, this is the system that monitors ALL of your hardware, and if the BIOS doesn’t see it, neither will windows. It is also in control of clockspeeds and you can enable/disable devices in it too. Every overclockers SHOULD know how to use the BIOS to the detail and SHOULD be in complete control of it. If you don’t have a clue as to what you’re doing, you had better do nothing at all.

• Overcharge

The settings you would be running for a benchmark, you can’t run this stable 24/7 and its merely bragging rights you attain by getting that higher benchmark score.

Ehm… Yeah that’s about it, you should know the terms I’m going to use in the OCing guide now, good luck!

Basic overclocking

• ONLY IF YOU OWN A DFI; READ THIS IN STEAD (more specific)

• Everything you do after this guide is at your own risk! I will not take responsibility for any of your escapades.

• Example Rig: DFI NF4 Ultra-D / Athlon64 Venice 3000+ / PC3200 ram

• You need to know what your CPU and ram will do independent of each other. Depending on which chipset you have (see “HTT” under the things you have to know) a maximum HTT link speed, the idea is the same but I’ll explain this with the described system. The maximum speed you will ever let this run at is 1Ghz. There are two settings in your bios that are interesting in your bios for now. The “HT”, and the “Multiplier”. Both settings may be on auto, shift them a bit to verify you have the right setting, the HT should be 200, and the multi everywhere from 8 to 13, depending on which CPU you have. This 3000+ has a 9 multi.
• To see only the maximum of your CPU, you will have to rule out your Ram and motherboard. Therefore you must divide your ram to 200:100, you do this in a separate screen in your bios which can be called anything, name will most likely be “memory ratio” or similar. This means your ram is running half the speed of whatever you put your HT to. Now you have to rule out your HTTlink, because when this succeeds 1Ghz it may become unstable. As I told you it is based out of the HT, and a multiplier. As we are going to up the HT, we will simply drop the multiplier to make sure the link doesn’t succeed 1Ghz, use “3”, just to be foolproof. Stock it would be set to “5”. Now you have slowed down the rest of your system enough to start finding the maximum of your CPU. Assuming you are using the stock cooler, immediately set your Vcore from 1.40 to 1.45 (this is perfectly safe, as long as your temperatures stay below 50C you can even go to 1.50, but no more on the stock cooler). Leave your CPU multiplier (or CPU ratio) at “9”, the maximum. Now you start upping the HT (the 200Mhz setting) by 5Mhz at a time. Everytime you have done so, boot to windows and run a program like Prime95 (free, for download see bottom, or google it) for 15 minutes. If the system is still stable then, you can up the HT another 5Mhz. If prime95 crashes in the 15 minutes you are running it, lower the HT by 5Mhz again and run Prime95 for an hour. If this is stable you can continue with the rest of the overclocking guide.
• Now you have a nice overclock on your CPU, but the rest of the system is totally screwed up. So, the first thing we need to know is exactly how far we got. Lets say we achieve 275x9, which is the same as 2475Mhz. The 275Mhz on the HT gives a problem or two with the HTTlink, as you can’t possibly run 275x5, that would crash big time. 4x275 is also more than 1Ghz, 1100Mhz to be exact. So we just keep the 3x multi, which results in 275x3=825Mhz. So we lost 175Mhz on this link, sad, but no problem. 825Mhz is more than enough to carry all the data and getting this higher doesn’t give much advantage at all.
• Now for the ram. It is PC 3200 and we can’t expect it to run 275Mhz at decent timings. So we’ll have to divide it, as its fairly complicated, don’t worry about the timings for now. Enable SPD in bios and divide the ram to 200:150, this will result in it running 220Mhz, SPD will take care of the timings.

• Now you are done OCing your system! This is what you got:
• CPU: From 1.8Ghz to 2.48Ghz
• Ram from 200Mhz to 220Mhz/slacked timings
• HTT to suit

• The CPU’s overclock is 675Mhz, nothing to spit at.

Tweaking on...

Now you probably noticed that I wasn’t telling you to push everything very hard. That’s because it takes up much more time to get every last bit out of the computer. I’m not going to give you entire stories again, you just take the basic guide I told you to follow, and I’ll tell you what to add.

• Finding the CPU’s max:

Go on until you find the approximate maximum. Now lower the HT by 5Mhz and continuously keep upping by 1Mhz, checking for stability every time. Whenever there is unstability up your Vcore by the tiniest step possible, and beware of your temps not exceeding the maximum. Continue this until you hit a solid wall, because your temps are getting out of boundaries. This is your CPU’s real maximum.

• The max HTT:

Unless you have the chipset watercooled, or very well aircooled, you shouldn’t touch the Vdd, the chipsets voltage. But if you have it that well cooled, you can up this voltage and actually run your chipset at up to 1100Mhz, it is just a chip that can be OCed. There is little advantage to this though so it isn’t very advisable.

• Tweaking the Ram:

This is slightly more difficult. Be advised you can up your Vdimm to create more stability. Now you have to rule out your CPU and chipset, and run the ram 1:1 at different timings every time (prime timings: 2-2-2-5, 2-3-2-6, 2.5-3-3-8) and find the max on each combination of timings. Lets say your ram will do 225Mhz on 2-2-2-5 (lowest possible), but when you use the 200:166Mhz divider your ram would end up at 230Mhz, and with the 200:150 divider it runs at 220Mhz. Right in between, damn it. So now you have to play around. Upping the Vdimm slightly may enable the ram to run 230Mhz at 2-2-2-5, that would be nice. But what if you were already at the max Vdimm? Then you might want to see if there is an advantage to sacrificing a bit of timing and gaining that 10Mhz, try running 2-2-2-6 or 2-3-2-5 for example. If that doesn’t work either, and you have to sacrifice too much, you should just use the 2-2-2-5 timings and the 200:150 divider, sad to loose that 5Mhz but sometimes you don’t have much of a choice.

• Of course this was a test system and the results were just thought of, but it is a perfectly attainable result. When I type it like this and you follow the exact actions I described, OCing looks like a laugh to you is my guess. But try doing it without this guide, and completely on your own. Getting the maximum possible out of that rig is harder than you think, especially finding the overcharge is hard because you don’t stresstest the CPU, you just see if it can run a specific benchmark before jamming up and that can take a lot of time to figure out. Usually the overcharge lies about 100Mhz higher than than the max stable speed.

Well, now that that's out... I could understand if newbies didn't quite get all this, I'm typing it through a knowledgeble mind. Those who still have to learn may indeed not quite get it, but as long as you got the basics, you're cool.

FAQ for Newbs

• Thnx to the people that thought of questions too simple to think of myself ;)

Q - How can I test whether my overclock is stable?

A - Download Prime95 and run that. This tests your CPU to the max, which folding does aswell. To test your memory's stability download Memtest86 and run that. If you have the DFI Lanparty UT you can download the Memtest86 bios update and use that. Links for downloads can be found at the bottom of this post.

Q - How long do I run Prime95 to be sure my CPU is stable? A - For at least 6 hours, 24 is seen as superstable.

Q - Is using the 1T memory setting the best option?

A - YES, 2T will slow you down a lot. About 20Mhz in ram speed is generally estimated.

Q - What is the maximum Vcore I should give my CPU?

A - As long as your CPU stays below the maximum temperature, 1.7Vcore is generally accepted to be the max to give your CPU on Xtreme air, meaning at least using a Tornado. If you're not an extreme case like a lot of us 1.60-1.65Vcore will get you fairly far.

Q - What is the maximum load temperature before I should get worried?

A - 55º is commonly seen as the max, for benching (max ~15 minutes load) 60-65 is acceptable.

Q - Is better timings better than lots of bandwidth?

A - In the A64's case, mostly yes. Meaning running 240HTT with your ram 1:1 at 3-4-4-8 will be slower than 240HTT ram 200:166 at 2-2-2-5. Dividing itself doesn't hurt much because the ram on an A64 is permanently divided, no matter what you do.

Q - Which multi should I use when overclocking?

That's a simple calculation, after finding out what your MAX CPU clock is (steps discribed above), fiind you max HTT while lowering the multi well beyond the limit, to something like 7 or 8. When you find your max HTT re-up the multi untill it gets the CPU as close to the max as possible. You may have to lower HTT a bit so you can maximize your multi, that may be better for performance. Just play around a bit.

Q - How do I use Dual Channel?

A DC MoBo has 4 memory slots, Slot 1 and 2 are channel 1, slot 3 and 4 are channel two. Slot 1 is the one closest to the CPU. If you fill slot 1 and 2 you will be running Single channel, if you fill slot 3 and 4 the same. If you want to run dual channel you need to use 1 and 3 or 2 and 4 or whatever, one slot from channel 1 and 1 slot from channel 2. If you feel the need to stash full all four slots (which is highly unneccesary and limits OCability) you will be automatically running Dual Channel.

Notes: The Ram should be the same, different speeds or size mean the slowest ram is used, and 512 and 256MB sticks can't run Dual Channel, unless you use 1 512MB stick, and two 256MB sticks in the other channel. All the ram uses the same timings so if you have one bad stick, don't use it. It'll slow down your entire system, but that's the same as with Single Channel.

Useful Links

CPU's

• Central Brain Identifier, CPU-Z and WCPUID:They do the same thing, monitor your CPU status and specs. This is the best guideline to telling the more knowledgeble people what you are facing or what you've managed. CBI and CPU-Z are most helpful, WCPUID a tad less...
• Clockgen: A real time adjuster of HTT, resulting in a new CPU speed, HTT and memory speed, but sadly, if you don't have a PCI/AGP lock, this program wont help you further.
• Prime95: A tester of whether your all new overclock is stable, of course we at EOCF encourage you to start folding in stead!!

Memory

• A64 Tweaker: A nice real time adjuster of memory settings in windows, for A64's of course. Its quite advanced and not very newb recommended.
• Memtest86: Put on a boot disk and run it when NOT BOOTED into windows, it tests your memory to the max with a result of it being stable or not. Doens't do anything else by the way.

General

• Motherboard Monitor 5: THE program for monitoring your temperatures and PSU rails, but its not always entirely accurate and not compatible with all motherboards, sadly.

• [Linky kapuchi? PM me on The Forums

--XT-ChAce 14:43, January 24, 2006 (CST)