16bit RAM Vs 32bit

manicx · 16 March 2005, 13:46

Recently, I acquired a ZII ram card (DataflyerRAM) with 8MB ram. This was from a A2000. I was needing some more ram for my A4k but I am happy with the standard 68040 and all I wanted was 8MB RAM to gain what is lost from OS3.5 + extras. This works in 16bit address. How much do I lose when it comes down to accessing 16bit instead of 32bit and will this result in stability problems? So far, I have no problems...

keropi · 16 March 2005, 19:33

LOL, u got it finally! :P

alexh · 16 March 2005, 20:46

I am guessing here...

Zorro II is a 16-bit DATA bus, Zorro III is a 32-bit DATA bus, so at the same bus speed that is an instant 50% loss.

The best Zorro II card design (zero wait states) could push 3.5Mbytes/sec and the best Zorro III card can push 12Mbytes/sec

In theory the ZII RAM card is 1/3rd speed of a ZIII one.

Jope · 17 March 2005, 08:26

Hmm.

The only stability issues I can think of are, if the RAM board's address space isn't cacheable.. However since it's RAM, it probably is. :-D

Cache problems are usually related to Zorro II IO cards running in Zorro III machines.

It'll just be slow, but you probably won't lose stability unless some of the RAM on the card is bad.

manicx · 17 March 2005, 09:09

I checked the SIMMs and I have a backup of 30pin SIMMs so no probz. Thanks for the answers. I will only lose some speed once this RAM is accessed so that's not a problem either...

Wepl · 17 March 2005, 10:04

Quote:

Originally Posted by manicx

Recently, I acquired a ZII ram card (DataflyerRAM) with 8MB ram. This was from a A2000. I was needing some more ram for my A4k but I am happy with the standard 68040 and all I wanted was 8MB RAM to gain what is lost from OS3.5 + extras. This works in 16bit address. How much do I lose when it comes down to accessing 16bit instead of 32bit and will this result in stability problems? So far, I have no problems...

the 16 MB on the mainboard will be faster
and any accelarator board with own memory will be a lot faster, so better try to get cheap 68040 board without cpu

16-bit ram halfs the transfer rate, this ram will be slower than your chipmem.

just use SysSpeed or similar to check

I think this Zorro-stuff is irrelevant because the memory is mapped into the address space, but I'm not sure.

manicx · 17 March 2005, 11:50

Well, I know that there are RAM boards made by DKB that run in ZIII mode. However, ZIII was cutting a bit of its speed and was running to about 80% of the fast RAM.

What should I look for in SysSpeed?

alexh · 17 March 2005, 23:33

I have a Zorro III DKB3128 if you want any speed ratings?

manicx · 18 March 2005, 08:57

No it's okay Alex. Arghhh, you got one of those DKB3128s. Hard to find...

Wepl · 18 March 2005, 08:58

Quote:

Originally Posted by manicx

What should I look for in SysSpeed?

you could compare memory speed from chip against fast to see if the fast is slower

16 March 2005, 13:46	#1
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	16bit RAM Vs 32bit Recently, I acquired a ZII ram card (DataflyerRAM) with 8MB ram. This was from a A2000. I was needing some more ram for my A4k but I am happy with the standard 68040 and all I wanted was 8MB RAM to gain what is lost from OS3.5 + extras. This works in 16bit address. How much do I lose when it comes down to accessing 16bit instead of 32bit and will this result in stability problems? So far, I have no problems...

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16 March 2005, 19:33	#2
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	LOL, u got it finally! :P

16 March 2005, 20:46	#3
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,478	I am guessing here... Zorro II is a 16-bit DATA bus, Zorro III is a 32-bit DATA bus, so at the same bus speed that is an instant 50% loss. The best Zorro II card design (zero wait states) could push 3.5Mbytes/sec and the best Zorro III card can push 12Mbytes/sec In theory the ZII RAM card is 1/3rd speed of a ZIII one.

17 March 2005, 08:26	#4
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,927	Hmm. The only stability issues I can think of are, if the RAM board's address space isn't cacheable.. However since it's RAM, it probably is. :-D Cache problems are usually related to Zorro II IO cards running in Zorro III machines. It'll just be slow, but you probably won't lose stability unless some of the RAM on the card is bad.

17 March 2005, 09:09	#5
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	I checked the SIMMs and I have a backup of 30pin SIMMs so no probz. Thanks for the answers. I will only lose some speed once this RAM is accessed so that's not a problem either...

17 March 2005, 11:50	#7
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	Well, I know that there are RAM boards made by DKB that run in ZIII mode. However, ZIII was cutting a bit of its speed and was running to about 80% of the fast RAM. What should I look for in SysSpeed?

17 March 2005, 23:33	#8
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,478	I have a Zorro III DKB3128 if you want any speed ratings?

18 March 2005, 08:57	#9
manicx Junior Member Join Date: Oct 2002 Location: Athens, Greece Posts: 991	No it's okay Alex. Arghhh, you got one of those DKB3128s. Hard to find...

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