None. Stick to late 90nm Windsor with F3 stepping (some 5200+and all 5600/6000/6400).

The only ones worth the effort were the 'Black' editions (unlocked multiplier)

Brisbane X2 3600+ 😁
They went to about 2.8-2.9GHz on default voltage, so 900MHz overclock ... but not much beyond that regardless of voltage increase.
You need MBO than can do 300MHz FSB.

But yes, Windsor F3 was better. Mature 90nm SOI process. Part numbers ending with CZ, for example ADA5600IAA6CZ.
I think F3 had soldered IHS, so no thermal problems. Brisbane had paste, and broken internal temp probe (offset of about 20°C if I remember correctly).

Only Brisbane Black has unlocked multipliers, but it just sucks.

analog_programmer wrote on 2023-10-04, 10:29:

I'm asking for advise which processor of these would be best for overclocking on air and why.

Check for a beta BIOS for your motherboard.
Some AM2 mobo had BIOS with support for AM2+ processors.
And there you can take Sempron AM2 +/AM3 and get 4GHz.
Well, or Phenom II x4 (x6) and get performance.

The Serpent Rider wrote on 2023-10-04, 10:39:

None. Stick to late 90nm Windsor with F3 stepping (some 5200+and all 5600/6000/6400).

Sorry, but I can't find F3 revision Windsor core (or any other Athlon 64 X2) for such a low price.

giantclam wrote on 2023-10-04, 10:43:

The only ones worth the effort were the 'Black' editions (unlocked multiplier)

Wrong answer. But anyway, thanks that you remind me how pathetic were "black" editions from this generation 😀

stef80 wrote on 2023-10-04, 10:48:

Brisbane X2 3600+ :D They went to about 2.8-2.9GHz on default voltage, so 900MHz overclock ... but not much beyond that regardl […]
Show full quote

Brisbane X2 3600+ 😁
They went to about 2.8-2.9GHz on default voltage, so 900MHz overclock ... but not much beyond that regardless of voltage increase.
You need MBO than can do 300MHz FSB.

But yes, Windsor F3 was better. Mature 90nm SOI process. Part numbers ending with CZ, for example ADA5600IAA6CZ.
I think F3 had soldered IHS, so no thermal problems. Brisbane had paste.

Listed CPUs are what I can buy for cheap and I don't want to invest wrong money into this system. The mobo is Abit KN9 nForce4 Ultra with overclocking options. Thanks for the detailed info!

shevalier wrote on 2023-10-04, 10:52:

Check for a beta BIOS for your motherboard. Some AM2 mobo had BIOS with support for AM2+ processors. And there you can take Semp […]
Show full quote

Check for a beta BIOS for your motherboard.
Some AM2 mobo had BIOS with support for AM2+ processors.
And there you can take Sempron AM2 +/AM3 and get 4GHz.
Well, or Phenom II x4 (x6) and get performance.

Unfortunately there's no support for Phenoms on this KN9 mobo in the beta BIOS (found one on Soggi's site) and there's no modded BIOSes.

analog_programmer wrote on 2023-10-04, 11:04:

Listed CPUs are what I can buy for cheap and I don't want to invest wrong money into this system. The mobo is Abit KN9 nForce4 Ultra with overclocking options. Thanks for the detailed info!

Had X2 3600+@2.85GHz on exactly this mbo 😀. It was the cheapest X2 I could put together new. MBO has Rubycon capacitors and heatpipe OTES cooling, so you're good.
Keep the BIOS on v1.2 if pushing for 300MHz FSB. And don't install Nvidia's firewall with nForce drivers. Forceware v5.10 if I remember correctly.

Why don't you take the fastest of them and be happy with it? Or for that price take all of them?

stef80 wrote on 2023-10-04, 11:26:

analog_programmer wrote on 2023-10-04, 11:04:

Listed CPUs are what I can buy for cheap and I don't want to invest wrong money into this system. The mobo is Abit KN9 nForce4 Ultra with overclocking options. Thanks for the detailed info!

Had X2 3600+@2.85GHz on exactly this mbo 😀. It was the cheapest X2 I could put together new. MBO has Rubycon capacitors and heatpipe OTES cooling, so you're good.
Keep the BIOS on v1.2 if pushing for 300MHz FSB.

Thanks again for your advise, stef80! I can no longer remember exactly which processors I've used on this board when it was actual about 15+ years ago, and I sold them long ago. The only things I remember are that I first had some Windsor (not of the top models) that was overclocked on air to about 3,2 GHz and later I made a mistake and changed it to a Brisbane that wasn't better.

You're tempting me to chose Brisbane 4400+ just to see if it will pass 3 GHz "border" 😀

doubt it will, but you can try

HanSolo wrote on 2023-10-04, 11:28:

Why don't you take the fastest of them and be happy with it? Or for that price take all of them?

Because overclocking was not so easy back then. All of the listed CPUs are with locked multipliers (I think with locked maximum multipliers) and there's meaning in DDR RAM divisors, etc. So, I decided to ask here which one from listed CPUs is the best one for overclocking with potential to go to 3-3.1 GHz on air with DDR400 only by FSB overclock.

And I do not need all of them, just to wonder later how to get rid of three unnecessary CPUs 😁

stef80 wrote on 2023-10-04, 11:42:

doubt it will, but you can try

So, which one from these two Brisbanes - 5400+ or 5600+? If i remember correctly, the locked multiplier on this generation Athlons can go down from maximum locked value, am I right?

I think they all had similar limits, that's why 3600 was the best 😉.

So, which one from these two Brisbanes - 5400+ or 5600+?

Doesn't really matter, same stepping. Although, Brisbanes with x.5 multipliers have weird issues with memory dividers which can provoke OCD.

The Serpent Rider wrote on 2023-10-04, 12:03:

So, which one from these two Brisbanes - 5400+ or 5600+?

Doesn't really matter, same stepping. Although, Brisbanes with x.5 multipliers have weird issues with memory dividers which can provoke OCD.

Interesting. I don't remember any problems for these Athlons with non-integer multipliers. Please, explain what you mean with "OCD"? And also, what it will be, if the multi is reduced to integer value i.e. from 14.5x to 14x or 13x, if it is possible (IIRC it was possible, but I'm not 100% sure due-to "faded memories")?

The windsor will probably do highest percent overclock, but that only might leave it a little behind or level with the 5400, 5600s have always been a PITA for me, maybe because of that half multi thing, so I'd go with the 5400 when restricted to those choices. I've got a 6000 or 6400 to use with my plain AM2 rig, think that's NF4, but also a little ripper of a AthlonII X2 260, which is unallocated, so if it turns out I can patch BIOS for that, I will.

There was tool for AM2 CPUs to calculate FSB/memory dividers. Will post if I manage to dig it up.

I see, maybe I'm fooling myself that locked multi on the Athlon 64 X2 can be lowered from the maximum locked value i.e. they're not with fixed multipliers. I have factory non-locked Athlon XP Barton (socket A) and its multi can go down and up to a certain values. And of course I still use Phenom II X6 which can go down from the locked max value for the multiplier and that's why I'm wrong that the locked Athlons 64 (X2) could also have their multipliers lowered. Can someone confirm this, please?

BitWrangler wrote on 2023-10-04, 12:53:

The windsor will probably do highest percent overclock, but that only might leave it a little behind or level with the 5400, 5600s have always been a PITA for me, maybe because of that half multi thing, so I'd go with the 5400 when restricted to those choices. I've got a 6000 or 6400 to use with my plain AM2 rig, think that's NF4, but also a little ripper of a AthlonII X2 260, which is unallocated, so if it turns out I can patch BIOS for that, I will.

This particular Windsor seems that has no chance to beat Brisbane 5400/5600+. If these are with fixed multipliers (no option to go down from maximum locked value) I'll take the 5400+. If there's option to go down from 14.5x - 5600+.

I've read on other forums quite a lot about modding of NF4 mobos for Phenom support. Seems that there is no way to insert AGESA code into the BIOS if not already done by manufacturer.

BitWrangler wrote on 2023-10-04, 12:53:

so if it turns out I can patch BIOS for that, I will.

I'd also love to be able to mod my AM2 BIOS for AM2+ or even AM3. Later Phenoms are just so much faster than the Athlon 64s.

@analog_programmer
you can always do that