Overclocking 68882

[paul1981]

Is there a real benefit of overclocking the 68882? I have a 50mhz 030 board and the 68882 actually overclocks and works fine up to 66mhz. What programs use the co proc? is it really worth overclocking?
 
thanks

The overclock will be beneficial to programs that are designed to use the 68882.  Like 3d rendering software/graphics/fractals and some audio software too.  But you have to make sure that when you install such software that you select the option (if available) that your computer has a maths co processor (FPU).  You must do this or it will install the Integer (non FPU) version, and your 68882 will be sat there generating alot of heat and for nothing!

Programs that I use that make use of the FPU are Vistalite, VistaPro, Distant Suns and Audio Evolution.  Also, I have a Squirrel SCSI interface which I have a cdrom drive connected....the squirrelscsi.device driver I am using is the FPU version (comes in FPU, 68000 and 68020 versions).  So even device drivers and the like can make use of the FPU if there is such a version available.
But for general use, overclocking the FPU will achieve nothing UNLESS you are using an FPU specific version of your program.

[paul1981]

Any recomendation on what to tress test with?

If you use AIBB and render the beachball, and there is no graphics corruption in the render...then according to AIBB documentation, your FPU is working correctly.

I bet the 68882 is running hot though, and I highly recommend either using a heatsink or a fan to keep it cool.

[paul1981]

I did run the beachball and it was fine, did it 5 times in a row. Actually the 68882 does not seem much hotter than normal (50mhz)

Then I'd say it's working, but I wouldn't go above 66 unless you are prepared to buy a replacement FPU when you fry it!

You can also get FPU specific versions of Lha and Zip/Unzip etc etc.  Have a look on aminet.

[paul1981]

And that is why I asked originally, is there really any befefit. the answer seems to be no.
I guess now I will; try to get the CPU to hit 66mhz or more

The answer is yes, there is a benefit.  Programs that are written directly for the 68881/68882 (like the ones I have mentioned) WILL run substantially faster at 66MHz.

[paul1981]

If you decide to play it safe, then why not settle for 60MHz on both CPU and FPU?  That's a 20% speed increase which is substantial.  But make sure you keep the CPU and FPU cool, and any other IC's which generate heat.