Slow/Fast RAM difference

Galaxy · 25 August 2005, 04:47

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.

DrBong · 25 August 2005, 06:01

I don't emulate, but could it refer to 16 bit vs 32 bit memory perhaps?

adolescent · 25 August 2005, 07:33

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.

Toni Wilen · 25 August 2005, 08:10

Address space is also different, 0xc00000-> when real fast is 0x200000->

Thread moved.

malko · 15 December 2017, 21:21

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

.

25 August 2005, 04:47	#1
Galaxy Registered User Join Date: May 2004 Location: Canberra, Australia Age: 46 Posts: 1,417	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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25 August 2005, 06:01	#2
DrBong HOL / AMR Team Member Join Date: Dec 2001 Location: Australia Posts: 2,632	I don't emulate, but could it refer to 16 bit vs 32 bit memory perhaps?

25 August 2005, 07:33	#3
adolescent Powered by Motorola Join Date: Feb 2002 Location: Redondo Beach, CA Age: 52 Posts: 1,065	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.

25 August 2005, 08:10	#4
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,517	Address space is also different, 0xc00000-> when real fast is 0x200000-> Thread moved.

15 December 2017, 21:21	#5
malko Ex nihilo nihil Join Date: Oct 2017 Location: CH Posts: 4,887	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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