The regular 485DX5-133 (=5x86-PR75) isn't particularly hard to come by, particularly not when compared to the Cyrix 5x86-133, but an ES is quite special. Don't think it will give you any advantages when running, so you are probably best off letting a collector enjoy this and using a normal one for actual running.

dionb wrote:

The regular 485DX5-133 (=5x86-PR75) isn't particularly hard to come by, particularly not when compared to the Cyrix 5x86-133, but an ES is quite special. Don't think it will give you any advantages when running, so you are probably best off letting a collector enjoy this and using a normal one for actual running.

Thanks! Just the answer I was looking for.

Looks like blatant rip-off, not the real engineering sample. AMD-X5 wasn't trademarketed.

The Serpent Rider wrote:

Looks like blatant rip-off, not the real engineering sample. AMD-X5 wasn't trademarketed.

It looks different in print style then the production chips that I have seen. But it does have the same print style as this engineering sample: https://www.engineering-sample.com/gallery/AM … 40_am486dxl280/

Intel engineering samples got some practical benefit after week 34 1998, when intel introduced clock locking of all their retail chips. Before that the practical difference is nearly nothing. AMD also implemented multiplier locking later on, but there were still ways to get around that with AMD chips.

Tried a Pentium 4 engineering sample last week, it was rather boring in clock options: 12x minimum, 21x maximum. I was hoping for some interesting underclocking, but it does not get below something that can be achieved by manually invoking intel speedstep. An AMD Mobile K7 or K8 allows for way more.

I would say that the person that is offering that trade is going to be coming out way ahead as something like that would probably sell for a tidy sum on eBay or other market places.

Assuming it's real it should be valuable. I'd have CPU-World check it out to see if it's real or fake.

There's also possible attempt to destroy AMD part number which is 25462.

The Serpent Rider wrote:

There's also possible attempt to destroy AMD part number which is 25462.

I can see it just as well as the cpu align dot next to it and the other logo in the bottom right corner. Nothing looks altered to my eyes.

Anonymous Coward wrote:

Assuming it's real it should be valuable. I'd have CPU-World check it out to see if it's real or fake.

I've made a post over there.

Looks pretty much self made but maybe that was the style of that department - nice find.

Keith1212 wrote:

Anonymous Coward wrote:

Assuming it's real it should be valuable. I'd have CPU-World check it out to see if it's real or fake.

I've made a post over there.

Link?