There's a K6-3+ 550 on the Dutch website Tweakers.net, but it is _expensive_

On the other hand, I accidentally bought a K6-3 450 (non plus) in a batch of computers. Mounted on an Asus P5A-B board. Still working great!

Do they do come around, but your best chance to keep it affordable is buying unidentified stuff. 😜

H3nrik V! wrote on 2021-06-16, 15:27:

A 333? Is that a 95 or 66 MHz FSB? (or both?)

[Edit] Apparently, google is my friend .. It can run both, it seems 😀

It is slightly over 95 MHz.
A SS7 board supporting all AMD CPUs properly has to support both 95 and 97 MHz.

I was able to get some K63+ 450 CPUs about two years ago for about $30 each.
But they are hard to find today for a good price.
Your best bet is to get some K6-2 which you can still find.

waterbeesje wrote on 2021-06-16, 20:53:

There's a K6-3+ 550 on the Dutch website Tweakers.net, but it is _expensive_

In the seller's defence: it is pretty unusual, a 550ACR rated at 2.0V. They tend to go for very inflated prices. That said, this one's been on sale for quite a while now and no one seems willing to offer close to the asking price.

Also, the K6-3+ is the end of the line CPU for Socket 7, and as with all CPUs where that is the case, the prices get wildly inflated. Be patient and you'll likely find a decent deal. Not quite a year ago I bought k6-3+ 450 for $32.99 on Ebay, and in Oct. of 2019 I got a K6-2+ 533 for $11.45.

From what I recall the K6-2 design was running out of steam by the time they hit 450 mhz and the added cache was all that made them any faster hence the K6-3 model name.

Here's my K6-2 at 375 (it's not stable at 400)

maxtherabbit wrote on 2021-06-17, 01:08:

Here's my K6-2 at 375 (it's not stable at 400)20210502_220557.jpg

You tried 83 MHz x 4,5 which may overclock PCI / AGP
Can you try 95 MHz x 4 or 97 MHz x 4 too?

Although I haven't checked this week, the last several times I bought one they were neither expensive nor rare (which surprised me, because I never saw these in the wild back when they were new). On CPU-World a year or two back they had a huge lot of the 1.6v versions going for next to nothing. I still see those ones pop up frequently for about what I paid (I want to say around $15).

Joseph_Joestar wrote on 2021-06-16, 07:58:

A Pentium MMX 166 can go down to 386DX-25 speed with both caches disabled. I've tested mine with the original Wing Commander and 3DBench2 and it's working as expected.

I think capability of some CPUs to downclock is overhyped. On these old boards it means changing jumper settings which is not that great as AT cases tend to be quite small, having poor access to jumpers. Disabling caches should be preferred.

AlexZ wrote on 2021-06-17, 05:46:

Joseph_Joestar wrote on 2021-06-16, 07:58:

A Pentium MMX 166 can go down to 386DX-25 speed with both caches disabled. I've tested mine with the original Wing Commander and 3DBench2 and it's working as expected.

I think capability of some CPUs to downclock is overhyped. On these old boards it means changing jumper settings which is not that great as AT cases tend to be quite small, having poor access to jumpers. Disabling caches should be preferred.

This is the precise reason why I like rack mount cases. Baby AT cases plain suck to work with.

Unknown_K wrote on 2021-06-17, 00:43:

From what I recall the K6-2 design was running out of steam by the time they hit 450 mhz and the added cache was all that made them any faster hence the K6-3 model name.

Yes they really don't scale in terms of performance much past 450MHz or so. The K6-3 is better as the cache runs at full speed but you still have the chipset limitations unfortunately.

I collected my K6's over 10 years ago and have quite a collection. Lost count really, but some from what I remember are below.

K6-III 333, 4 of 400, 2 450AFX and 2 450AHX. Fastest I got on air was 500 out the 450AFX's

K6-2+ 400ACR, 400ATX, 4 of 500ACZ, 2 of 550ACZ

K6-III+ 400ATX, 4 of 450ACZ, 1 of 500ANZ Fastest I got was with the 500ANZ at either 6x103fsb or 5.5x112 on an Epox MVP3 G2 with L3 cache still enabled. The 400ATX only got to 550 stable.

Stedman

How do I get in contact with that guy on Tweakerz? 😀

also, what is the "embedded" line of K6?
Aren't they ss7? Usually, when I hear embedded, I imagine they are a different package and soldered on a board...

DraxDomax wrote on 2021-06-17, 11:49:

also, what is the "embedded" line of K6?
Aren't they ss7? Usually, when I hear embedded, I imagine they are a different package and soldered on a board...

https://pccomponents.com/amdk6FAQ.asp

"Advanced Micro Devices (AMD) has produced microprocessors from two internal groups within AMD. Microprocessors which include an E in the part number were produced by AMD's "Embedded" Group. Those that do not have an E in the part number were manufactured by AMD's "Desktop PC" group.
Microprocessors manufactured by the "Desktop PC" group were marketed to compete with microprocessors produced by other manufacturers, especially Intel. The pricing structure, warranty, and support programs offered by AMD were therefore designed to be competitive in this market.
Microprocessors manufactured by the "Embedded" group were marketed to companies who designed products that used a microprocessor as part of its integral design. Typical embedded applications might include a Sony PlayStation, cash register, or Access Control System. To make the product more desirable to these groups AMD offered a long term availability guarantee, lower power and higher temperature versions, and often added addition support and or registers desirable to the embedded market.
It is important to understand that the designation "Desktop PC" or "Embedded" has nothing to do with application restrictions. Parts produced by the Desktop PC group can certainly be used in Embedded applications and vice versa.
The only area of concern that many end users have when deciding whether to purchase a part produced by the Desktop PC group or the Embedded group is that AMD has documented that internal changes are often made to allow Embedded product to operate reliably at higher temperatures or lower voltages, and we know that AMD often offered a longer warranty to embedded customers, but the actual changes made to offer a longer warranty are almost always undocumented.
In addition, some Embedded product enhancements included support for new instructions and/or registers or even functional changes,
There is no standard answer for how Embedded microprocessor differs from non-embedded product. The only way to tell for sure is to compare the data sheets of the specific Desktop PC and Embedded Product. If you will be replacing a microprocessor in an existing design and you do not have the time of ability to compare the individual data sheet you can play it safe by using an Embedded microprocessor as the Embedded part is always the same or a better part.

I have a small AMD K6 collection, a K6 200, K6-II 400 2.2V, K6-III 400 AFR with 2.2V, a K6-III+ 400 ACR 2.0V and the K6-III+ 500 ANZ 1.8V.
The 400 ACR runs prime stable with 550 MHz and ~2.2V and the 500 ANZ works in one of my retro systems. It runs prime stable with 550 MHz (1.8V) and 600 MHz with 1.95V.

If you search ebay for "K6 400ATZ" the lowest price for brand new AMD-K6-III+/400ATZ is 70USD at the moment. Stock voltage is 1.6 and rising the voltage a bit it can easily be overclocked to 550MHZ.

janih wrote on 2021-06-17, 18:25:

If you search ebay for "K6 400ATZ" the lowest price for brand new AMD-K6-III+/400ATZ is 70USD at the moment. Stock voltage is 1.6 and rising the voltage a bit it can easily be overclocked to 550MHZ.

Yeah, but who wants a K6-3+ for $70? Already costs 3x what it should.

Disruptor wrote on 2021-06-17, 03:21:

maxtherabbit wrote on 2021-06-17, 01:08:

Here's my K6-2 at 375 (it's not stable at 400)20210502_220557.jpg

You tried 83 MHz x 4,5 which may overclock PCI / AGP
Can you try 95 MHz x 4 or 97 MHz x 4 too?

I like having the buses overclocked, it makes them faster 😀

I don't have those other FSB as options to try