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AmigaHope · 10 March 2020, 15:33

I wanted to share something here because it's been overlooked a lot by a lot of people. Most Amiga setups have very poor mass storage bandwidth (it seems most people are using a Gayle-style IDE interface) despite having fast processors coupled with fast memory access.

AmigaOS, all the way from 1.0 to 3.1.4/3.9 has had a long of history of poor mass storage caches. The OS implements a read-only cache system, and by default most people never use it to its full potential. This has its roots in the 1980's era of RAM-starved systems, where buffers were kept lean to avoid excessive memory allocation.

Floppy drives, hard drives, flash memory, whatever you use have a read-only buffer. On floppy drives this is configured automatically, and on mass storage this is configured in your mountlist (with the Buffers line) or on the autoconfig mountlist stored in RDB (also Buffers line). You can easily enlarge this using the AddBuffers command. If you have a modern Amiga with a lot of memory, just make this HUGE. e.g. if your system has 128M of memory, give your partitions 10M+ each of buffers and you'll notice the performance improvement.

Even better, use a more modern writeback buffer system like PowerCache or FDA. Your workbench performance will improve by a factor of 10, and any heavily storage-interactive software will improve similarly. You'll also see this performance improvement in games that use the OS routines (whether floppy or hard disk).

The reason for this is that, without exception, the performance on Amiga mass storage controllers is terrible. It's particularly terrible if you're using one on the Amiga's motherboard bus (e.g. A1200 IDE controller, most Gayle emulators, etc.), and even on fast IDE controllers like FastATA the bandwidth is bad and the CPU usage is huge. Even if you have a fast DMA SCSI controller on your CPU card (e.g. Cyberstorm) there's still a bottleneck. None of it can compete with RAM.

The crazy thing is that installing Powercache or FDA can even somewhat improve performance on WinUAE where all the devices are virtualized and executed out of RAM on the host system. The latency improvement helps even then.

If you have an Amiga with some RAM to spare, even sparing a few megabytes on a 32M system, give improving the caches a try. You'll notice the difference immediately. Even if you just give it a few megabytes.

On my A4000 with CyberstormPPC using UltraSCSI/160 drives on the DMA bus, it still made a night and day improvement in general operations.

10 March 2020, 15:33	#1
AmigaHope Registered User Join Date: Sep 2006 Location: New Sandusky Posts: 942	Best Amiga performance via storage cache I wanted to share something here because it's been overlooked a lot by a lot of people. Most Amiga setups have very poor mass storage bandwidth (it seems most people are using a Gayle-style IDE interface) despite having fast processors coupled with fast memory access. AmigaOS, all the way from 1.0 to 3.1.4/3.9 has had a long of history of poor mass storage caches. The OS implements a read-only cache system, and by default most people never use it to its full potential. This has its roots in the 1980's era of RAM-starved systems, where buffers were kept lean to avoid excessive memory allocation. Floppy drives, hard drives, flash memory, whatever you use have a read-only buffer. On floppy drives this is configured automatically, and on mass storage this is configured in your mountlist (with the Buffers line) or on the autoconfig mountlist stored in RDB (also Buffers line). You can easily enlarge this using the AddBuffers command. If you have a modern Amiga with a lot of memory, just make this HUGE. e.g. if your system has 128M of memory, give your partitions 10M+ each of buffers and you'll notice the performance improvement. Even better, use a more modern writeback buffer system like PowerCache or FDA. Your workbench performance will improve by a factor of 10, and any heavily storage-interactive software will improve similarly. You'll also see this performance improvement in games that use the OS routines (whether floppy or hard disk). The reason for this is that, without exception, the performance on Amiga mass storage controllers is terrible. It's particularly terrible if you're using one on the Amiga's motherboard bus (e.g. A1200 IDE controller, most Gayle emulators, etc.), and even on fast IDE controllers like FastATA the bandwidth is bad and the CPU usage is huge. Even if you have a fast DMA SCSI controller on your CPU card (e.g. Cyberstorm) there's still a bottleneck. None of it can compete with RAM. The crazy thing is that installing Powercache or FDA can even somewhat improve performance on WinUAE where all the devices are virtualized and executed out of RAM on the host system. The latency improvement helps even then. If you have an Amiga with some RAM to spare, even sparing a few megabytes on a 32M system, give improving the caches a try. You'll notice the difference immediately. Even if you just give it a few megabytes. On my A4000 with CyberstormPPC using UltraSCSI/160 drives on the DMA bus, it still made a night and day improvement in general operations.