Quote:
Originally Posted by sandruzzo
030 50mhz or even 28 mhz?
|
Assuming the 030 accesses RAM using the same number of clock cycles as the 68k (which is false, it uses less), at 28MHz it will have a RAM bandwidth around four times higher than the 68k (28 = 7 * 4, 7mHz = original clock frequency).
If you run a mem copy in a tight loop which fits into the cache, this means that it is not slowed down too much by instruction fetches and will almost have this full bandwidth available for data reads and writes. This is grossly the same speed as the blitter with its four (3 read, 1 write) channels.
(If you write to chip RAM you would have to take into account that that its bandwidth is limited in addition to being used by the chips as the Galahad kitten hinted.)
Sure, this is just a back of the envelope approximation but this gives a reasonable idea of what to expect.
Hope this helps.
