Pedal to the Metal: Overclocking the Athlon AM2

This is an excellent guide man, the table of AM2 memory dividers is especially interesting. I will definitely pass this on to friends who are upgrading and lack current OCing experience. Props for putting this out for the community.
 
VERY, VERY well done guide! Can I get a sticky for the OP?
 
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Thanks for the support guys :) Glad to hear its been a help

Peace
 
The guide may be available on a well-known host soon, I will update the thread later as needed :)

Peace
 
The RAM dividers work the same way on S939.

Good guide... you do very good work.

Oh.. I was one of them people that was overclocking in '96.. I think I actually did it a bit before them.. like in '92 or '93.

First CPU I overclocked was a 80486 25Mhz to 33Mhz.... I saw a jumper on the motherboard that said 25Mhz and 33Mhz... I was like.. hmmm, I wonder if it will run at
33Mhz... so I changed the jumper.. and it did.

The Heatsink didn't get any hotter than normal.. course I could touch it in the first place without burning my fingers.. so it seemed pretty much the same afterwards.

After that I was hooked. Every system since then I have overclocked.

I had a 486 33Mhz that I overclocked to 40Mhz

Then I overclocked another 486.. a DX2-66 to 80Mhz... the motherboard which I used had been thrown away cause somebody spilled coffee on the system... I sprayed it down with rubbing alchohol untill it ran clean and then let it dry for a day.. It worked flawlessly.

Then a 5x86 133 to 160Mhz

After that, I went to the K6 platform and had a blast.... Most of the original K6 processors would only clock 50Mhz higher than stock.. but I had a 300 that I got to run at a bit above 400. :)
Then after a while I had a K6-2 550 running at 660.

When I worked at a computer store.. we got some of those K6-2 333 processors in... They would run at 500Mhz on stock volts.. just bumped up the bus speed from 66 to 100.

Then I went the the Slot-A Athlon systems.. I had one running at 1.13Ghz.

Then I went to the socket A processors... I had quite a few of those... experimented a lot.. killed a lot.. but at $50 a pop.. who cared.

Then the Athlon XP processors.. those were nice.. especially the 2500+ and 3200+ bartons... the 2500+ would usually run at 3200+ speeds with little to no voltage increase.. and I could get a 3200+ up to 2.6Ghz with high end air.

And then I got a A64 3700+ and stuck it up to 2.75Ghz.. and now I have the system that is in my sig :)
 
The RAM dividers work the same way on S939.

First CPU I overclocked was a 80486 25Mhz to 33Mhz.... I saw a jumper on the motherboard that said 25Mhz and 33Mhz... I was like.. hmmm, I wonder if it will run at
33Mhz... so I changed the jumper.. and it did.

How could you tell, did it have a large red or green LED clock freq display on the case front panel? :)
 
How could you tell, did it have a large red or green LED clock freq display on the case front panel? :)

Nope, the boot screen showed 33Mhz instead of 25Mhz.. and stuff ran faster.

BTW... the old clock freqency displays were manually configured by jumpers.. you could make them say anything you wanted to.
 
That sounds like the internal jumper for the TURBO button, hehe.

Ahhh... turbo switches.. I miss those days.

If I remember right it was a Compaq... they sold two models... one with a 25Mhz chip and one with a 33Mhz chip. Evidently they used the same motherboard.

Hehe... on the 486DX2-66 that I ran at 80, I actually ran a wire with a plug on both ends and modded the case so I could switch between the 33Mhz and 40Mhz bus speed.. So yeah.. that one was set up like a turbo switch.

For regular stuff, I would run it at 66.. for games, I would pump it up to 80.
 
not bad, but i personally find it WAY too wordy. i wouldn't have the patience to sift through all the talk and explanations if i was learning how to overclock with this guide... plus, there are a few things here and there that make me scratch my head. ;)

first thing i noticed is that you are basing this entirely off an asus bios. you should give other names for the options listed. like you have "cpu frequency", which is most commonly referred to as the htt or fsb speed. saying that cpu speed = cpu frequency * cpu multiplier is wrong and circular. :p

now.. ram is somewhat my specialty these days, so of course i'm gonna notice things there. If your memory is rated for DDR2-800 at 4-4-4-15, with 2.0v, it wil NOT automatically set the voltage for you, as you say. voltage is not an option in the SPD tables. if you have EPP memory, and a board that supports it, it may or may not set the correct voltage. however, setting the memory voltage is something that must be done yourself.

for the memory ratios, there is never any guesswork. instead of referring to the table all the time, just remember this equation:
memory speed = cpu speed / x
x = ceiling( cpu multiplier / memory ratio)

where the memory ratio is 2:1 for ddr2-800, 5:3 for ddr2-667, 4:3 for ddr2-533 and 1:1 for ddr2-400.

that way, it fills in the blanks for what happens if amd releases cpus with a ddr2-1066 ratio, or if you're using a 1/2 multiplier


for the memory timings, you say that lower is better, which is true, at a given memory frequency. however, i find that AM2 LOVES high ram clocks over tight timings. it's almost always better to loosen the timings to 5-5-5 and ramp up the clock speed as much as possible. recommend to them that trying various timing and speed combinations and testing each one for performance levels is the best way to go

Command rate is a very misunderstood timing. it has very little to do with the memory, but instead is dependent on how strong your memory controller is. good luck getting much over 450-500mhz stable at 1T with the current generation of memory controllers, with two sticks in. with four (double sided) sticks, forget it, the load from addressing 8 ranks of memory is too much unless the ram is around 200mhz :p

bank/rank interleaving, i've always found that disabling it decreases stability, even though it shouldn't. ;)

about temperatures... gah. temperatures. there is no "one" value that your cpu cannot tolerate higher than. as a general rule of thumb, for every 10ºC hotter the processor runs, the lifespan will be cut in about half. this is true for all CMOS based circuits actually. the thing is, voltage too has a large effect on this, with the lifespan varying with the square of voltage. the problem is, the original lifespan at stock settings and a given temp is not known, so you have to guess and see how risky you want to be. the values you quote are more temperatures used to establish the stability of the chip. since the maximum stable speed decreases as temperature rises (assuming a constant voltage), they rate the processor as being stable at a specific voltage, speed and temperature. if you go over that temp, it may or may not be stable at stock speed/voltage. in my experience, it usually is. however, the chips can definitely tolerate temps past 100ºC. for how long, i don't know, but probably longer than a few months. most seem to think they'll die almost instantly at those temps, when it's just not true. silicon is much more resilient than is realized ;)


that stuff aside, it's pretty thorough, and just might be better than my own guide that i wrote forever ago that was unstickied for some unknown reasons :p
 
not bad, but i personally find it WAY too wordy. i wouldn't have the patience to sift through all the talk and explanations if i was learning how to overclock with this guide... plus, there are a few things here and there that make me scratch my head. ;)

As a matter of personal opinion, I have always found it more advantageous to give more than is necessary and allow one to sift through for what they're looking for than not giving enough ;)

first thing i noticed is that you are basing this entirely off an asus bios. you should give other names for the options listed. like you have "cpu frequency", which is most commonly referred to as the htt or fsb speed. saying that cpu speed = cpu frequency * cpu multiplier is wrong and circular. :p

I believe that I made a note of this, and the difficulty in selecting an appropriate method to detail settings (i.e. software utility vs BIOS; which BIOS to choose, etcetera). I'm going to be playing with an M2R32-MVP pretty soon, so I'll take a look at what it calls these settings. The nForce series seems to be one of the most popular, so I think that most of the AM2 market is *probably* seeing the same/VERY similar settings in BIOS.

now.. ram is somewhat my specialty these days, so of course i'm gonna notice things there. If your memory is rated for DDR2-800 at 4-4-4-15, with 2.0v, it wil NOT automatically set the voltage for you, as you say. voltage is not an option in the SPD tables. if you have EPP memory, and a board that supports it, it may or may not set the correct voltage. however, setting the memory voltage is something that must be done yourself.

Hmm, I see what you're saying. I think that I gave a little too much credit to the motherboard there, LOL. As a quick hit, I did point out that setting it as close to its stated voltage would be best, and if it didn't post, giving it a little more may help and so on and so forth, but, :(

for the memory ratios, there is never any guesswork. instead of referring to the table all the time, just remember this equation:
memory speed = cpu speed / x
x = ceiling( cpu multiplier / memory ratio)

I was debating whether or not to actually include the equation and leave it at that or give it in tabular form. I settled on just giving the memory ratios as a function of the multiplier selected because it seemed to be easier at the time. There are some people out there, believe it or not, who have no idea what the ceiling and floor functions are.

for the memory timings, you say that lower is better, which is true, at a given memory frequency. however, i find that AM2 LOVES high ram clocks over tight timings. it's almost always better to loosen the timings to 5-5-5 and ramp up the clock speed as much as possible. recommend to them that trying various timing and speed combinations and testing each one for performance levels is the best way to go

First, this really wasn't a guide on memory overclocking, that's why I didn't get too in-depth on cranking it up. In fact, I largely recommended just running the RAM at its stated speeds for beginners. In any case, I think that it was made clear that the *general* rule may be to have the tightest timings, but if somebody is looking to run their RAM at a higher speed, they will have to loosen timings and/or add voltage.

Command rate is a very misunderstood timing. it has very little to do with the memory, but instead is dependent on how strong your memory controller is. good luck getting much over 450-500mhz stable at 1T with the current generation of memory controllers, with two sticks in. with four (double sided) sticks, forget it, the load from addressing 8 ranks of memory is too much unless the ram is around 200mhz :p

Yeah, there was a Corsair rep who pretty much reminded me of the same thing yesterday. While I have indicated that 1T is nice, I think I made it clear that one should be completely (realistic) prepared to set it to 2T in any case.

about temperatures... gah. temperatures. there is no "one" value that your cpu cannot tolerate higher than. as a general rule of thumb, for every 10ºC hotter the processor runs, the lifespan will be cut in about half. this is true for all CMOS based circuits actually. the thing is, voltage too has a large effect on this, with the lifespan varying with the square of voltage. the problem is, the original lifespan at stock settings and a given temp is not known, so you have to guess and see how risky you want to be. the values you quote are more temperatures used to establish the stability of the chip. since the maximum stable speed decreases as temperature rises (assuming a constant voltage), they rate the processor as being stable at a specific voltage, speed and temperature. if you go over that temp, it may or may not be stable at stock speed/voltage. in my experience, it usually is. however, the chips can definitely tolerate temps past 100ºC. for how long, i don't know, but probably longer than a few months. most seem to think they'll die almost instantly at those temps, when it's just not true. silicon is much more resilient than is realized ;)

I certainly wasn't trying to say that running at the limit of the safe operating temperature specified by AMD was the absolute maximum the chip could physically handle, HOWEVER, I advised examining the system configuration if it was running that hot because running at/next to these temperatures for an extended period could be problematic.

that stuff aside, it's pretty thorough, and just might be better than my own guide that i wrote forever ago that was unstickied for some unknown reasons :p

Thanks for the feedback :)
 
Plus, you've got a rubbish speedo on the front page of the guide. 110!?!?!

ROFL, trust me, the designer who did the graphic (based on my lame specifications, no less) was not impressed by my concept or the fact that the picture I had her take was of my speedometer at 0, LOL.

Hey, it's the effort that counts ;)

- Atif
 
As a matter of personal opinion, I have always found it more advantageous to give more than is necessary and allow one to sift through for what they're looking for than not giving enough ;)
yeah, i totally hear you on this one. i'm lazy. the little table of contents in the beginning makes it much easier anyhow, otherwise i would have given you a lot more crap for it. remember that many overclockers are borderline ADD and seem to have very little patience :p


I believe that I made a note of this, and the difficulty in selecting an appropriate method to detail settings (i.e. software utility vs BIOS; which BIOS to choose, etcetera). I'm going to be playing with an M2R32-MVP pretty soon, so I'll take a look at what it calls these settings. The nForce series seems to be one of the most popular, so I think that most of the AM2 market is *probably* seeing the same/VERY similar settings in BIOS.
yeah, all the boards label things differently, but within a brand, things tend to stay very consistant. i find it easiest to try to find screenshots of various BIOSes and explain what each of the settings in that BIOS does. then almost everyone is happy. for example, from the guide you gave, someone with the board i own, a dfi lanparty nf590, would be totally clueless:

genie.png


which htt speed and multi to change?! there's two sets of each :D
obviously, it can be figured out through trial and error, but it's a bit intimidating at first to see a lot of options that are labeled very differently than what you're reading


I was debating whether or not to actually include the equation and leave it at that or give it in tabular form. I settled on just giving the memory ratios as a function of the multiplier selected because it seemed to be easier at the time. There are some people out there, believe it or not, who have no idea what the ceiling and floor functions are.
it's not hard to explain, round up or round down :D
since you've written so much already, i don't see why adding the equation along with the table would be any serious issue :p



First, this really wasn't a guide on memory overclocking
<snip>
yeah, i hear ya. i'm just biased in these matters, since memory is kinda my life these days :p


I certainly wasn't trying to say that running at the limit of the safe operating temperature specified by AMD was the absolute maximum the chip could physically handle, HOWEVER, I advised examining the system configuration if it was running that hot because running at/next to these temperatures for an extended period could be problematic.
and i was trying to say that the 'limit' for all these chips are about the same. amd's number is only saying what the rated speed is specified for, nothing in the least about how much temperature it can tolerate. you implied that 65nm and 90nm chips can take a different amount of heat, which is silly, because it's still the same material, constructed the same way. the transistors are just smaller :D



Thanks for the feedback :)
anytime man. it's about time someone else on here wrote up a good a64 overclocking guide ;)
 
@eclipse - Post AM2 OC thread link please.
I'd like to make a consolidated sticky, like the one we had in the S939 days.
 
@eclipse - Post AM2 OC thread link please.
I'd like to make a consolidated sticky, like the one we had in the S939 days.

i'll let you know when i give it a proper update, it's shamefully incomplete these days ;)
 
Odd. It used to be a sticky, I guess it was un-stickied recently

Peace
 
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