Math chip
3 messages in this thread
I've got an A2500 with the 2620 board. How much of a perform I expect if I
replaced my 14 MHz 68881 with a math chip with a faster clock speed?
On page 4-61 of the Motorola 68000 Family Reference Record book, it says
that the MC68882 has 1.5 times the performance of the MC68881. Not sure
this is what you wanted to know exactly, but it appeared to be the right
thing.
Are you the Albert Yen I know? Brother of Angela and Terry?
Betty
Albert,
Funny you should ask that! I just replaced my 68881 with a 25 MHz
68882. I ran a few tests with Imagine and came up with the following:
Running the 68882 at 14 MHz reduced my rendering times by about
25%.
Running the 68882 at 25 MHz reduced rendering times by anywhere
from 33% to 41% (again, when compared with a 14 MHz 68881).
To give you some real numbers, I rendered a 1/4 screen HAM image of
a glass. In unaccelerated mode it took 2:43:17 (hh:mm:ss). Using the 14 MHz
68881 took 00:38:02. Using the 25 Mhz 68882 took 00:22:25.
Does this answer your question?
Robert Fisher