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Old 25 August 2005, 05:47   #1
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Slow/Fast RAM difference

What exactly is the difference between what WinUAE terms slow and fast ram.

I note that what I have always considered fast RAM is referred to as slow RAM in WinUAE.

Back in the Amiga days, RAM was only ever referred to as Chip or Fast RAM - I don't ever remember seeing reference to slow RAM.

I always thought the distinction was Chip RAM = mem used by processor and custom chips; fast RAM = mem for exclusive use by processor.

Your Amiga came only with chip RAM, and most RAM expansions were detected/advertised as fast RAM. (although you could run patches to turn one sort into another (chip up to the max limit allowed by your Agnus chip) or mod the mobo.
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Old 25 August 2005, 07:01   #2
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I don't emulate, but could it refer to 16 bit vs 32 bit memory perhaps?
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Old 25 August 2005, 08:33   #3
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Slow RAM is RAM that is on the Chip RAM bus, but is treated like Fast RAM allowing only the CPU to access it (although accessed like Chip RAM because it's on the Chip RAM bus). For example, the A501 trapdoor expansion is Slow RAM.

Edit: hopefully someone can clarify if I've worded it incorrectly.
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Old 25 August 2005, 09:10   #4
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Address space is also different, 0xc00000-> when real fast is 0x200000->

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Old 15 December 2017, 22:21   #5
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Even if it is an old thread, looking at the options available under FS-UAE, I came to the same question and found a quite good explanation here.
Hope it is useful for someone else .
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