What is this CPU?

[randomx]

Hi all,

This is out of a broken iMac slot load. Shows as a 600mhz 750cxe in the OS, however I’ve never seen a chip with the crosses on it.

Any ideas?

 

[Phipli]

Hi all,

This is out of a broken iMac slot load. Shows as a 600mhz 750cxe in the OS, however I’ve never seen a chip with the crosses on it.

Any ideas?

Sometimes manufacturers regrade a chip when they have surplus of one type and sales of another.

For example, they might take a 400MHz at 70°C chip and re print it as 500MHz at 50°C.

That might have happened with yours. Although they seem to have kept the speed grade the same and changed the bit before that is probably the temperature grade? Not sure without spending a while reading datasheets.

 

[randomx]

Interesting… I might try and run it at a higher clock and see if it plays ball … if the original speed rating is anything to go by it was designed for higher than 700mhz…

 

[Compgeke]

It's very possible it's also just from a batch of chips that failed QC at the initial rated speed. It's not uncommon for chips to be binned lower when they fail to meet some spec or another (like the early 486 SXs that just had a bad FPU that disabled).

 

[herd]

The chineez are much better at relabeling chips. Send it there and it will come back as a brand new chip rated for 1GHz

...thanks for sharing the picture and good luck with your experiments.