SEC 68000 BOOSTER 64 & 75MHz CPU
Posted: 01 May 2020 14:37
In all tests below, CPU only was running faster and ROM is basically the bottleneck and limited to 32MHz. ST RAM is still running at stock speeds.
64MHz
75MHz
These tests were slightly slower because of wait states had to be added onto ROM access which pushed ROM access speed down to 309% from 368%. important figure is basically integer division anyway.
75MHz + OC ROM
The above test was with ROM basically overclocked to get it back to 368%.
In comparison to the simple 8/32MHz STE booster...
It is of no real surprise that 64MHz CPU only doesn't give much increase across tests. But I thought I would post this information here as it is still quite interesting just the same. If ROM could run at 64MHz then there would be again another fair speed gain there, but currently it's not really possible. It is also currently questionable at what the point of diminishing returns is in terms of ROM access. from 8Mhz to 16MHz there is about 25% speed gain in tests. 16MHz to 32MHz is again about 25% more. But 32MHz to 64Mhz may not yield a additional 25% again. The underlying problem to all this is the bottleneck of ST-RAM.
64MHz
75MHz
These tests were slightly slower because of wait states had to be added onto ROM access which pushed ROM access speed down to 309% from 368%. important figure is basically integer division anyway.
75MHz + OC ROM
The above test was with ROM basically overclocked to get it back to 368%.
In comparison to the simple 8/32MHz STE booster...
It is of no real surprise that 64MHz CPU only doesn't give much increase across tests. But I thought I would post this information here as it is still quite interesting just the same. If ROM could run at 64MHz then there would be again another fair speed gain there, but currently it's not really possible. It is also currently questionable at what the point of diminishing returns is in terms of ROM access. from 8Mhz to 16MHz there is about 25% speed gain in tests. 16MHz to 32MHz is again about 25% more. But 32MHz to 64Mhz may not yield a additional 25% again. The underlying problem to all this is the bottleneck of ST-RAM.