UPDATED 28th November 2005! Top downloads at bottom!
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Look at the bottom of this post for older S754 overclocking.
 
This guide includes overclocking of the new opteron chips that are currently in the headlines. Here are my findings:
 
Good clocking cpu's are 144,146 and 148 opterons. Try and get an 0540 one if you can!
 
Corsair 3500LLPRO PC 3500 2x1gb is amazing memory. Can run 220mhz 2-3-2-5 timings and upto 250mhz 2.5/3/3/8!
 
Freezer 64, SLK 90 and 120 are top air coolers!
 
Test Setup.
Opteron 144 CAB2E 0540 FPMW
Freezer 64 cooler
DFI NF4 Ultra D latest bios
2x512mb OCZ pc3200 EL 2/3/2/6 @ 2.5/3/3/6
 
Make sure to keep processor temperatures under 55C! Speedfan is good for monitoring.
 
First off I purchased the processor second hand pre tested @ 2.8ghz 1.44v so I lowered the ram:HTT ratio to 7:10 and the HTT ratio to x3.
 
This means that because I know the memory can do 230mhz (tested in an older motherboard) I can reach a theoretical 329mhz HTT before I encounter ram limitations. 329/10x7 = 230mhz.
 
Now I set the HTT to 300 in the bios, cpu voltage to 1.47 (actual is 1.44) which gives me 300x9 = 2700mhz. Windows boots fine as I know the HTT and ram are ok and the cpu has been pre tested to 2.8ghz but I am trying 2.7 just to be safe.
 
I use clockgen for NF4 to raise the HTT 2mhz at a time then run prime95 for 20 minutes and if it passes I raise the HTT again until it fails.
 
I reached 313mhz HTT and 2817mhz before prime failed at the 15 minute mark. Dropping the HTT back to 311 gave me a prime stable CPU.
 
To test the memory for its max overclock - I suggest using these settings:
 
200mhz HTT x3 = 600mhz
1:1 memory:HTT ratio
 
This way the memory can be overclocked with clockgen without the cpu reaching 2.8ghz because the memory would need to do 311mhz 1:1 which is pretty impossible unless you are using PC 4800 memory or similar.
 
If you have good memory that you think will reach over 300mhz then set the CPU multiplier to x7.
 
Overclock using clockgen 2mhz HTT at a time or more if you feel brave until prime95 will not pass 20 minutes. This should give you your max memory overclock.
 
Lets say the memory ran ok at 235mhz. We know our CPU ran ok at 2.8ghz so we can now use 311x9 = 2799mhz with a 3:4 memory:HTT ratio (or 150mhz setting).
 
311/4x3=233mhz memory.
 
Here are my results.
Click!
 
 
 
You can also mess about with the max HTT speed by lowering the cpu multiplier to 7 and ram to 1:2 and see how far the HTT will overclock.
 
Heres a guide to memory:HTT settings.
 
Ratio / HTT@200mhz/300
 
1:2 = 100mhz/150mhz
3:5 = 120mhz/180mhz
2:3 = 133mhz/200mhz
7:10 = 140mhz/210mhz
3:4 = 150mhz/225mhz
5:6 = 166mhz250mhz
9:10 = 180mhz/270mhz
 
Hope this helps!
 
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PART 2 - 2-13-04
 
This is the old guide for S754 overclocking!
 
I think this guide is essential as a lot of people will be asking how these new chips from AMD overclock. Heres a guide on how to go about it and an ideal setup to achieve top results. I will be focusing on the 754 single channel processors.
 
First off some information on the Athlon 64.
 
The A 64 3000,3200 and 3400 come in socket 754 configuration and only work with 754 motherboards. The 3200 and 3400 have 1mb of cache and the 3000 has 512kb of cache.
All the socket 754 cpu's have an onboard single channel memory controller to reduce latencies and increase performance. Being single channel the 754 processors do not need 2 sticks of memory for maximum performance.
 
An ideal list of components to achieve top results.
 
One thing to keep in mind is that the N-force 3 and Via K8T 800 motherboards do NOT have a lock on the pci bus. The N-force 3 boards do have locked AGP and a few of the VIA motherboards do aswell.
 Overclocking an Athlon 64 is not going to be as easy as overclocking an Athlon XP or Pentium 4, but with a bit of luck it should yield good results.
 
The memory needs to be capable of upto 230mhz FSB so some good quality PC 3700 memory will suffice. Choosing the motherboard will depend on what 3d card you have and how far you intend on taking the overclock.
 
 For all Nvidia owners, any motherboard will do for overclocking, especially the ASUS, Gigabyte and MSI boards.  
 If you have a radeon you may well want to go for a board with locked AGP bus to keep stability at 220mhz fsb. My 9700pro does 216mhz fsb fine but it may start to become unstable over this speed. An N-force 3 chipset motherboard should be used here if possible for 220mhz and over fsb overclocks.
 
The choice of processor is up to you. The 3200 and 3000 processors are multiplier locked to 10 so for whatever FSB speed you do achieve, multiply that speed by 10 and thats the maximum processor speed. For e.g my MSI motherboard based on the VIA K8T 800 chipset (no locked agp or pci bus) runs at 213mhz fsb stable which gives me a total overclock to 2130mhz from 2000mhz (213x10=2130mhz).
 
For a higher cpu speed a 3400 has the 11 multiplier to and in my motherboard would be doing 2343mhz instead of 2130mhz of my 3200.
 
Cooling is not really a problem as the stock cooler keeps an Athlon 64 cooled to 35-45C on average.
 
Heres a good budget overclocking setup.
 
A 64 3000 with stock cooler
512mb twinmos 3700 memory
Asus K8V Via motherboard
 
This setup will hopefully acheive 220mhz fsb.
 
The ideal overclocking setup
 
A64 3400
GIGABYTE GA-K8N PRO
Corsair PC 3700 memory
 
With a bit of luck 225mhz fsb + and 2.46ghz cpu speed can be achieved.
 
Final tips for overclocking.
 
A good way to start overclocking is to download clockgen for your Athlon 64 motherboard. With this you can overclock the FSB in windows, run PRIME95 and 3dmark 2001 for a few hours and then up the FSB some more. Once you have achieved a stable overclock, go into the BIOS and enter the FSB you achieved.  
 
To achieve a higher FSB you may raise the VDIMM (memory voltage) to 2.75V and lower the CAS (memory timings for advanced users only) to 2.5 or 3. Return to windows and try to overclock more and see if its stable.
 
******UPDATE******
Clockgen lets you lower the multiplier of an Athlon 64 so that you can run a higher HT (FSB) speed. For exmple I changed the multiplier to 9.5 and managed to raise the HT speed of my athlon cpu processor to 222mhz, but the AGP bus was too high for my 9700pro so it was unstable.  
 
******UPDATE******
 
I found that lowering my DDR speed to 333MHZ in the bios let me reach a high FSB speed and an overall faster system. I managed to get my HT speed to 231mhz prime and 3dmark stable which resulted in a cpu overclock of 309mhz from 2000mhz to 2309mhz. 3D mark 2001 proved this speed (231mhz HT, 2309mhz cpu speed and 192mhz memory speed)to be faster  
than 215mhz HT, 2150mhz cpu speed and 215mhz memory speed.
 
Key downloads.
 
Clockgen
Prime 95
Speedfan

Bump.

bump
 
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Speed... thats a nice u r running now, Congratulations! so u finally beat the 20k mark    
 
Hey, that clockgen is a cool piece of s/w, tnx for the link man.
 
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Hello mate. Yeah clockgen was handy for me too. BTW I broke 21k now <A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new">http://service.futuremark.com/compare?2k1=7584476</A>
 
 
<A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new"> My rig </A>

Congratulations man...
 
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Thanks =) And thats with the slower omega 4.1's and win xp. Probably get a few extra 100 points with 3.4 cat's and win 2000....
 
<A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new"> My rig </A>

lol... so whats ur next target? 22222pts?    
 
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Heh I think ill let the card recover first. Poor thing...
 
<A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new"> My rig </A>

Speedy who cares about the card, now aim for 25000 marks. Can't you overclock the CPU any higher?
 
-Intel PIV 2.6C @ 3.276G -Asus P4P800 -OCZ Copper 4x256 4000EL memory @ 252mhz 2.5-3-4-6  -XFX 5900 128meg 570/1040 -SB audigy -2x120G Seagate 7200.7 S-ATA150 hdd -450 Enermax PSU

Not until i get a pci/agp locked mobo.
 
<A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new"> My rig </A>

Scotty, whats new with ur rig mate! u beat speed's score?
 
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Can't FX5900 sucks d*ck.
 
-Intel PIV 2.6C @ 3.276G -Asus P4P800 -OCZ Copper 4x256 4000EL memory @ 252mhz 2.5-3-4-6  -XFX 5900 128meg 570/1040 -SB audigy -2x120G Seagate 7200.7 S-ATA150 hdd -450 Enermax PSU

Speedy, why don't you ask Fredi to make this sticky, so you don't have to bother typing bump all the time.
 
-Intel PIV 2.6C @ 3.276G -Asus P4P800 -OCZ Copper 4x256 4000EL memory @ 252mhz 2.5-3-4-6  -XFX 5900 128meg 570/1040 -SB audigy -2x120G Seagate 7200.7 S-ATA150 hdd -450 Enermax PSU

You got his email addy mate?
 
<A HREF="http://service.futuremark.com/compare?2k1=7584476" target="_new"> My rig </A>

just PM him, his name is Fredi.
 
-Intel PIV 2.6C @ 3.276G -Asus P4P800 -OCZ Copper 4x256 4000EL memory @ 252mhz 2.5-3-4-6  -XFX 5900 128meg 570/1040 -SB audigy -2x120G Seagate 7200.7 S-ATA150 hdd -450 Enermax PSU

where's the socket 939 OC guide?

 
I was searching for it also..  :?

The Opteron 1xx series are 939 pin and the best 939 chips for overclocking...