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Rarest CPUs?

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Reply 300 of 442, by Sphere478

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TrashPanda wrote on 2022-11-12, 13:28:
It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling. […]
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Nemo1985 wrote on 2022-11-12, 13:23:

That's cool, can it work without heatsink in your opinion?
My k6-3+ could run at 200 mhz and v1.3, the whole system consumption was under 30 watt.

It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling.

It’s worth investigating just how little cooling it requires at a range of low voltages and speeds.

Never had an embedded K6 variant before so I don’t know if AMD changed anything internally regarding power management.

In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a tillamook. (Under specific low volt/clock settings)

But a 2+/3+ is a close second.

I in fact have run a tillamook for some time without a heatsink.

Underclocking and undervolting help a lot

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 301 of 442, by TrashPanda

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Sphere478 wrote on 2022-11-12, 17:49:
In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a […]
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TrashPanda wrote on 2022-11-12, 13:28:
It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling. […]
Show full quote
Nemo1985 wrote on 2022-11-12, 13:23:

That's cool, can it work without heatsink in your opinion?
My k6-3+ could run at 200 mhz and v1.3, the whole system consumption was under 30 watt.

It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling.

It’s worth investigating just how little cooling it requires at a range of low voltages and speeds.

Never had an embedded K6 variant before so I don’t know if AMD changed anything internally regarding power management.

In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a tillamook. (Under specific low volt/clock settings)

But a 2+/3+ is a close second.

I in fact have run a tillamook for some time without a heatsink.

Underclocking and undervolting help a lot

I'm curious how low this 2+E can go for voltage and clock speed, 350 @ 1.5v is already lower than other E series 2+ and much lower than the stock 1.9v of a Tilly, I wonder if it would be stable at 200Mhz with the voltage as low as it can go.

As for sans heatsink, while I like the idea I wouldn't run even a Tilly without the bare minimum of a heatsink even if its a shitty ally one.

Reply 302 of 442, by Sphere478

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My tyan can do like 1.2? Volts? Lowest multi of a tillamook I think is 2.0

So potentially, 50x2 at 1.2 on my tyan.

Or maybe use my voltage interposer and a lab psu.

In any case, at 133 and 2.1v it’s basically cool enough to run without a heatsink

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 303 of 442, by ChrisK

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I've an AMD-K6-III+/400ATZ 1.6V (that's 9.5W TDP compared to 7.5W TDP of the AMD-K6-2+/350AUZ) running at 6x 83MHz and 1.65V, cooled by a passive Zalman chipset heatsink. It's blown by a low rev 80mm case fan from some distance. Not even getting hand warm. Could surely be run without the fan but it's a chip that's worth a bit, so less risk = more fun.
Wouldn't run it without any heatsink, as is the case for the Tillamook.

Reply 304 of 442, by TrashPanda

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ChrisK wrote on 2022-11-15, 14:31:

I've an AMD-K6-III+/400ATZ 1.6V (that's 9.5W TDP compared to 7.5W TDP of the AMD-K6-2+/350AUZ) running at 6x 83MHz and 1.65V, cooled by a passive Zalman chipset heatsink. It's blown by a low rev 80mm case fan from some distance. Not even getting hand warm. Could surely be run without the fan but it's a chip that's worth a bit, so less risk = more fun.
Wouldn't run it without any heatsink, as is the case for the Tillamook.

Yep, I wont be running it without some form of passive cooling, its a cool little CPU.

Reply 305 of 442, by Sphere478

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ChrisK wrote on 2022-11-15, 14:31:

I've an AMD-K6-III+/400ATZ 1.6V (that's 9.5W TDP compared to 7.5W TDP of the AMD-K6-2+/350AUZ) running at 6x 83MHz and 1.65V, cooled by a passive Zalman chipset heatsink. It's blown by a low rev 80mm case fan from some distance. Not even getting hand warm. Could surely be run without the fan but it's a chip that's worth a bit, so less risk = more fun.
Wouldn't run it without any heatsink, as is the case for the Tillamook.

Agree about k6-+ just a taddddd too much for no sink

But man, those tillamooks, I need to do a vid of underclocking and undervolting and running with no sink.

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 307 of 442, by Sphere478

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It would be so cool to one day get a new cpu for socket 7. I suspect that with advances in fpga we may one day get just that.

Technically the last socket 7 cpu was a intel product though.

It was never sold, more of a science experiment. And it ran at 50mhz I believe, but it was a modified intel atom running on fpga a team at intel did this for some reason.

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 308 of 442, by Jasin Natael

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Sphere478 wrote on 2022-11-15, 18:29:

It would be so cool to one day get a new cpu for socket 7. I suspect that with advances in fpga we may one day get just that.

Technically the last socket 7 cpu was a intel product though.

It was never sold, more of a science experiment. And it ran at 50mhz I believe, but it was a modified intel atom running on fpga a team at intel did this for some reason.

That is cool, I didn't know that.

Reply 309 of 442, by RaiderOfLostVoodoo

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ChrisK wrote on 2022-11-15, 14:31:

I've an AMD-K6-III+/400ATZ 1.6V (that's 9.5W TDP compared to 7.5W TDP of the AMD-K6-2+/350AUZ) running at 6x 83MHz and 1.65V, cooled by a passive Zalman chipset heatsink. It's blown by a low rev 80mm case fan from some distance. Not even getting hand warm. Could surely be run without the fan but it's a chip that's worth a bit, so less risk = more fun.
Wouldn't run it without any heatsink, as is the case for the Tillamook.

I have one of these as well.
Ran it at 4x100MHz and 1.6V, so stock settings. Fan wasn't plugged in. After 5 minutes of Prime95 I shut down the system and immediately removed the heatsink. Could barely recognize any warmth.
So yeah, these can definitely be used without a heatsink. But I also wouldn't recomend it. Just remove the fan and save yourself a few watt hours.

Reply 310 of 442, by Sphere478

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Can you do the test again without a heatsink?

Put some black electrical tape on the cpu and read it with a infra red thermometer

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 311 of 442, by debs3759

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RaiderOfLostVoodoo wrote on 2022-11-15, 22:16:
I have one of these as well. Ran it at 4x100MHz and 1.6V, so stock settings. Fan wasn't plugged in. After 5 minutes of Prime95 I […]
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ChrisK wrote on 2022-11-15, 14:31:

I've an AMD-K6-III+/400ATZ 1.6V (that's 9.5W TDP compared to 7.5W TDP of the AMD-K6-2+/350AUZ) running at 6x 83MHz and 1.65V, cooled by a passive Zalman chipset heatsink. It's blown by a low rev 80mm case fan from some distance. Not even getting hand warm. Could surely be run without the fan but it's a chip that's worth a bit, so less risk = more fun.
Wouldn't run it without any heatsink, as is the case for the Tillamook.

I have one of these as well.
Ran it at 4x100MHz and 1.6V, so stock settings. Fan wasn't plugged in. After 5 minutes of Prime95 I shut down the system and immediately removed the heatsink. Could barely recognize any warmth.
So yeah, these can definitely be used without a heatsink. But I also wouldn't recomend it. Just remove the fan and save yourself a few watt hours.

That just means the heatsink did its job, no evidence from that that it can be run without a cooler.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 312 of 442, by BitWrangler

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Sphere478 wrote on 2022-11-12, 17:49:
In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a […]
Show full quote
TrashPanda wrote on 2022-11-12, 13:28:
It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling. […]
Show full quote
Nemo1985 wrote on 2022-11-12, 13:23:

That's cool, can it work without heatsink in your opinion?
My k6-3+ could run at 200 mhz and v1.3, the whole system consumption was under 30 watt.

It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling.

It’s worth investigating just how little cooling it requires at a range of low voltages and speeds.

Never had an embedded K6 variant before so I don’t know if AMD changed anything internally regarding power management.

In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a tillamook. (Under specific low volt/clock settings)

But a 2+/3+ is a close second.

I in fact have run a tillamook for some time without a heatsink.

Underclocking and undervolting help a lot

Some of the later production P75-P100 ceramic barely need one @ 3.3V unless you wanna get 133-166 out of them of course. I think some of the split plane WinChips will just do it too.... It's all a bit "depends" on case ventilation and ambients.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 313 of 442, by Sphere478

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BitWrangler wrote on 2022-11-22, 01:44:
Sphere478 wrote on 2022-11-12, 17:49:
In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a […]
Show full quote
TrashPanda wrote on 2022-11-12, 13:28:

It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling.

It’s worth investigating just how little cooling it requires at a range of low voltages and speeds.

Never had an embedded K6 variant before so I don’t know if AMD changed anything internally regarding power management.

In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a tillamook. (Under specific low volt/clock settings)

But a 2+/3+ is a close second.

I in fact have run a tillamook for some time without a heatsink.

Underclocking and undervolting help a lot

Some of the later production P75-P100 ceramic barely need one @ 3.3V unless you wanna get 133-166 out of them of course. I think some of the split plane WinChips will just do it too.... It's all a bit "depends" on case ventilation and ambients.

You might be right I haven’t done much work with those chips in particular

Sphere's PCB projects.
-
Sphere’s socket 5/7 cpu collection.
-
SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 314 of 442, by Windows9566

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or the Intel Overdrive chips, do those count as Rare? or the Intel 486SX 16 or 486DX 25?

R5 5600X, 32 GB RAM, RTX 3060 TI, Win11
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Reply 315 of 442, by rmay635703

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Windows9566 wrote on 2022-11-22, 17:55:

or the Intel Overdrive chips, do those count as Rare? or the Intel 486SX 16 or 486DX 25?

Sx16 are uncommon but not really rare
just a bit uncommon, not surprising considering how pointless they were.
A desktop DX2-40 is actually rarer

If you can find a 486dx-20 those are rather rare considering their pre release status,
(I can’t remember if they were ever a retail release even)

F6F76158-2B85-426C-8CF0-7CD6C1A0EBEA.jpeg
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And good lord, this thing must be rare given it’s the ultimate in pointless

Reply 316 of 442, by debs3759

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rmay635703 wrote on 2022-11-22, 23:50:
Sx16 are uncommon but not really rare just a bit uncommon, not surprising considering how pointless they were. A desktop DX2-40 […]
Show full quote
Windows9566 wrote on 2022-11-22, 17:55:

or the Intel Overdrive chips, do those count as Rare? or the Intel 486SX 16 or 486DX 25?

Sx16 are uncommon but not really rare
just a bit uncommon, not surprising considering how pointless they were.
A desktop DX2-40 is actually rarer

If you can find a 486dx-20 those are rather rare considering their pre release status,
(I can’t remember if they were ever a retail release even)
F6F76158-2B85-426C-8CF0-7CD6C1A0EBEA.jpeg
And good lord, this thing must be rare given it’s the ultimate in pointless

That's a retail spec - s-spec starts with S

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 317 of 442, by rmay635703

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debs3759 wrote on 2022-11-23, 03:26:
rmay635703 wrote on 2022-11-22, 23:50:
Sx16 are uncommon but not really rare just a bit uncommon, not surprising considering how pointless they were. A desktop DX2-40 […]
Show full quote
Windows9566 wrote on 2022-11-22, 17:55:

or the Intel Overdrive chips, do those count as Rare? or the Intel 486SX 16 or 486DX 25?

Sx16 are uncommon but not really rare
just a bit uncommon, not surprising considering how pointless they were.
A desktop DX2-40 is actually rarer

If you can find a 486dx-20 those are rather rare considering their pre release status,
(I can’t remember if they were ever a retail release even)
F6F76158-2B85-426C-8CF0-7CD6C1A0EBEA.jpeg
And good lord, this thing must be rare given it’s the ultimate in pointless

That's a retail spec - s-spec starts with S

Why were some dx2’s just labeled overdrive with only a bus speed and no “speed rating”

Reply 318 of 442, by H3nrik V!

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rmay635703 wrote on 2022-11-22, 23:50:

F6F76158-2B85-426C-8CF0-7CD6C1A0EBEA.jpeg
And good lord, this thing must be rare given it’s the ultimate in pointless

The Overdrive "SX-20" is actually a DX2-40. First series of Overdrives were named after what they were supposed to replace, not what they were. IIRC, all 486 Overdrives are at least DX2's, which is also the case with the pictured "SX-20". https://www.cpu-world.com/sspec/SZ/SZ675.html

Please use the "quote" option if asking questions to what I write - it will really up the chances of me noticing 😀

Reply 319 of 442, by TrashPanda

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BitWrangler wrote on 2022-11-22, 01:44:
Sphere478 wrote on 2022-11-12, 17:49:
In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a […]
Show full quote
TrashPanda wrote on 2022-11-12, 13:28:

It’s designed for fanless embedded systems, at a lower speed and voltage I doubt it would need much if any cooling.

It’s worth investigating just how little cooling it requires at a range of low voltages and speeds.

Never had an embedded K6 variant before so I don’t know if AMD changed anything internally regarding power management.

In my experiments there is only one socket 5/7/ss7 cpu that could reasonably potentially be run without a heatsink and that’s a tillamook. (Under specific low volt/clock settings)

But a 2+/3+ is a close second.

I in fact have run a tillamook for some time without a heatsink.

Underclocking and undervolting help a lot

Some of the later production P75-P100 ceramic barely need one @ 3.3V unless you wanna get 133-166 out of them of course. I think some of the split plane WinChips will just do it too.... It's all a bit "depends" on case ventilation and ambients.

I have one of these 2.9v Pentium 90s, not sure itll even need a cooler as it barely gets warm when running.

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