WTB: 68882 50mhz FPU for Blizzard1230 MK4

[keropi]

As topic, I am looking for a 50mhz 68882 FPU for a MK4 1230 card. PM me if you have one for sale, thanks!  :-D

[alenppc]

Sometimes you can find them on Ebay but they are outrageously expensive. I am looking for a 40 MHz one, but am not willing to spend $80 on it...

[alexh]

If we can get 20 or so people (preferably all in Europe) interested we could order through Digikey or somewhere. Price should be around the €30 each mark

[Hodgkinson]

Amigakit did have some in stock a while back...

[tokyoracer]

I think mines 33Mhz but it's clocked at 50, never had issues with it at all. Doesn't get too hot either.

[McVenco]

tokyoracer wrote:
I think mines 33Mhz but it's clocked at 50, never had issues with it at all. Doesn't get too hot either.

The MHz printed on the chip is just a safety measure. 50MHz means it has been tested succesfully on 100MHz. If the 100MHz failed (too hot or something) they tested at 80MHz. If that was succesful they shipped it as 40MHz.

So basically, all those chips are pretty much the same...

[alenppc]

The MHz printed on the chip is just a safety measure. 50MHz means it has been tested succesfully on 100MHz. If the 100MHz failed (too hot or something) they tested at 80MHz. If that was succesful they shipped it as 40MHz.

So basically, all those chips are pretty much the same...

Um... no. If that were true those chips would be designed for 80 MHz, not 40.

The only safe frequency is the one printed on the chip itself. Granted, they often work at higher frequencies but the correct functioning cannot be guaranteed in every case.

I understand that few of us use Amigas in an environment that requires an absolute precision, but then again, I'd rather play it safe and make the chip last longer. Despite the popular but misguided practice of "overclocking" in the PC world, an overclock is NOT a free performance increase. You are paying for it in terms of stability and accuracy.

Actually, the reason I am looking for a 40 MHz FPU is because I have a 33 MHz clocked at 40 on my A600 accelerator, and I want to replace it with a proper one.

[alexh]

I doubt very much it would do anything for your stability.

Not having an FPU at all on an Apollo A600 accelerator helps stability.

[Damion]

alenppc wrote:

Despite the popular but misguided practice of "overclocking" in the PC world, an overclock is NOT a free performance increase. You are paying for it in terms of stability and accuracy.

It just depends, there are too many factors involved to make blanket statements one way or the other. I've had great success overclocking PCs, an old Athlon XP mobile chip of mine was *still* prime stable almost 5 years after a 600 MHz overclock. Other chips (like early "Venice" core AMD) aren't as robust. You just have to be careful, research and weigh the risks. Granted -- I wouldn't try to launch the shuttle on overclocked HW.