Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Effy on January 14, 2004, 06:55:45 AM
-
Would this GVP A2000-RAM8 MEMORY add memory to my A4000 without accellerator ??? Can I add as much Zorro2 ramcards as I want on a Zorro3 machine ??? I know Zorro2 is limited to 8 Mb and Zorro3 is not, but I'm not sure enough about it ...
http://www.amiga-hardware.com/gvp200028.html (http://www.amiga-hardware.com/gvp200028.html)
-
I do not have an answer to this question but I would like to add to it. What exactly is the difference between the GVP A2000 and GVP A4000 SCSI/RAM boards other than the chipset used? Also, what models can they be used on?
-
Same question actually, would this GVP Impact Series II 2000 HC+8 scsi controller work too ?? I can also supply 8 Mb Simm and a scsi controller, is not so fast as a Fastlane Z3 though ...
http://www.amiga-hardware.com/gvpimpactii2000hc8.html (http://www.amiga-hardware.com/gvpimpactii2000hc8.html)
-
slippymadfrog : this is what I found on The Big Book :
GVP Impact Series II 4000 HC+8
The main differences between this version and the 2000 HC+8 seems to the SCSI chipset used. The original card uses a western digital chipset whereas this card uses a DPRC chipset. The card also has 8 x 30pin SIMM slots for adding up to 8MB of additional RAM. The card can use either 1MB or 4MB 30pin SIMMs, however the maximum RAM you can add is still 8MB, even with 4MB SIMMs.
Is this enough as an answer ?? It's all I found ...
-
Sure every ZII card will work in a ZIII slot (unless it is one of those ZIII Micronics for the A1200, but this is another issue).
No matter how much ZII cards with RAM you add to a ZIII system you still could only add 8 MB max. this way.
The ZII adresspace lies within the adresspace of the ZIII bus and all ZII cards share this adressapce just as if they were in a real ZII bus.
ZII cards aren't a good way to add memory anyway, sice you could only squeze only about 5 MB/s out of ZII (and that is the theoretical value) .That is slower then a hardrive on a turbocard- or ZIII SCSI-controller
-
Does this mean that if I add a Ramcard with 8 Mb to my Z3 A4000 that I can not add a CV64/3D with 4 Mb ??? :-?
-
@Effy
The CV64/3D is a Zorro III card.
-
@Effy:
The CV64/3D will initialize as a ZorroIII-card in the A3000/A4000 and thus its memory will be mapped in the ZorroIII-range of adresses. This means that the Ramcard will not interfere with a CV64/3D.
I must just say that I dont recommend adding ram to an A4000 using a ZorroII card as it will be very slow and if used heavily it will eat up possible ZorroIII bandwidth for graphics-cards etc.
A ZorroII-card has a maximum theoretical transferrate of 3.5MB/Sec (if no special tricks are used as with the Delfina flipper). If a ZorroII-card is used in an A3000/A4000, the percentage a ZorroII-card uses of the maximum 3.5MB/Sec bandwidth will remove an equal percentage of the usable ZorroIII-bandwidth in an A3000/A4000.
To show the impact I am gonna give an example. Lets first assume that the maximum bandwidth of the Zorro-bus in a A3000/A4000 using ZorroIII-cycles is 16MB/Sec (its exact value doesnt really matter). I also assume that all cards used in this example are of no-waitstate type for the sake of easy comparision.
If a ZorroII-RAM-card uses 50% of its possible bandwidth during a given period of time (that would equal to 1.75MB/Sec), it would then during that given period of time remove 50% of the ZorroIII-bandwidth resulting in only 8MB/Sec (0.5 * 16) bandwidth being available for ZorroIII-cards.
Had this RAM-card been a ZorroIII RAM-card instead it would have left 14.25MB/Sec (16 - 1.75) of bandwidth availible for ZorroIII-cards.
/Patrik
-
So that would mean that using a scsi controller for the A4000 WITH ram on the card would be a lot better than using a Z2 scsi controller with ram ??? Like for example the GVP Impact Series II 4000 HC+8 ...
-
@Effy:
Well, the Impact Series II is quite special if I remember correctly, but it is still a ZorroII-card. The special thing about it is however that it in contrast to other ZorroII scsi-controllers do DMA transfers to/from SCSI disks directly to/from the memory on the board so the Zorro bus isnt utilized by this activity.
What I wanted to say basicly was that ZorroII-cards isnt exactly optimal to use in the Zorro bus of the A3000/A4000. Ofcourse it works fine, but it is very slow and it hogs the bus bandwidth enormously.
So if you have the possibility - avoid ZorroII cards which uses lots of bandwidth (ram expansions, harddrive controller, graphic cards, etc) in the A3000/A4000. ZorroII cards which uses little bandwidth like serial cards etc are perfectly ok to use in the A3000/A4000 though.
/Patrik
-
Usually RAM on an accelerator and on the A4000 mobo have a higher priority then RAM on a ZII card, so slowdowns will only occur when all the other RAM is used up and the ZII RAM has to be used.
The only ZII SCSI controller where it makes actually sense to have RAM on when installed in a ZIII System is the A2091, as this card makes DMA into ZII RAM. When there is not ZII RAM present it will lead to major slowdowns.
-
@Lemmink:
The reasons for slowdown with the A2091 and no ZorroII fastmem comes from the fact that the only thing ZorroII cards can DMA to/from in a ZorroIII system is chipmem and ZorroII fastmem. So the slowdown in that case comes from the fact that the A2091 is doing DMA to/from buffers in chipmem.
The reason why I am so anti ZorroII in a ZorroIII system is that the ZorroII cards use many times more "possible" bandwidth on the Zorro-bus than ZorroIII-cards. As I mentioned in an earlier post, the percentage of maximum ZorroII bandwidth a ZorroII-card uses is equal to the percentage of ZorroIII bandwidth that lost.
Only using a ZorroII ram-expansion would as you say not be used until all other faster memory is used, so a ram-expansion only would be ok I guess even if it is rather pointless.
Though using a ZorroII scsi-controller is very uneffective and there are a number of scenarios of uneffectiveness ;):
1. You have no ZorroII fastmem and a controller using DMA:
Data will be shuffled to buffers in chipmem over the Zorro-bus using DMA and then the cpu will be working on the buffers in chipmem.
2. You have no ZorroII fastmem and a controller not using DMA:
Data will be shuffled over the Zorro bus by the cpu to 32-bit memory and then the cpu will be working on the buffers in 32-bit memory.
3. You have ZorroII fastmem and a controller using DMA:
Data will be shuffled to buffers in ZorroII fastmem over the Zorro-bus using DMA and then the cpu will be working on the buffers in ZorroII fastmem.
4. You have ZorroII fastmem and a controller not using DMA:
Data will be shuffled over the Zorro bus by the cpu to 32-bit memory and then the cpu will be working on the buffers in 32-bit memory.
5. You have a special controller like the Impact series II:
Data will be shuffled to buffers in the memory of the Impact Series II card without touching the Zorro bus by the DMA and then the CPU will be working on the buffers in the ZorroII-memory of the Impact Series II.
Scenario 1 is extremely bad because of the chipmem and scenario 3 is extremely bad because of the double data transfers on the Zorro bus. Scenario 2 and 4 are also very bad because they need the cpu to do all the work, but it only hogs the bus half as much as scenario 3. Scenario 5 is the most sensible of them, but they are all bad from a performance perspective and a bus hoging perspective.
One more reason a ZorroII card is bad in a ZorroIII system is because the thing that makes DMA stand out is lost as ZorroII cards cant move data directly to the fastest memory closest to the cpu.
blablabla.. ;).
/Patrik
-
cybervision 64/3D is Z2/3 autodetect
-
Okay, I get the picture, no Zorro2 scsi controller with Ram in a Zorro3 busboard. Then why did GVP create that GVP 4000 HC+8 (http://www.amiga-hardware.com/gvpimpactii4000hc8.html) which is a Zorro2 card ???
-
Hi
> Then why did GVP create that GVP 4000 HC+8 which is a Zorro2 card ???
I've found no notice that this controller was made for the A4000. "GVP 4000" may imagine that, but it's nevertheless a ZII-Card for the A2000.
See also to http://amiga.resource.cx/exp/search.pl?dir=scsi
Noster
-
Hi Effy,
the short answer is: don't use 16 bit ZII memory on your A4000 (if you can).
16MB on mobo= PRI +30 Latency 8.1
8MB on ZII= PRI 0 Latency 20.7
2MB ChipRam= PRI -10
Quite ALWAYS, in the 16 bit Ram space= SLOOOOWWWW!!!
Ciao
-
This is my answer to all the help you guys gave me and I hope you will be happy now (http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&item=2780673171&category=8142&rd=1) :-D
Please don´t tell me I made a big mistake ...
-
@Effy:
This is my answer to all the help you guys gave me and I hope you will be happy now (http://cgi.ebay.nl/ws/eBayISAPI.dll?ViewItem&item=2780673171&category=8142&rd=1) :-D
:)
Please don´t tell me I made a big mistake ...
Excellent choice.
Have fun! :)
/Patrik
-
Hi Effy,
mistake?
You have done the best choise for your actual system :-)
The problems are basically 3:
1- you must use the 30 pins SIMMs in groups of four
2- 4 MB 30 pins SIMMs 60 ns are expensive (4 pcs= 50EUR used)
3- you need SB rev11 (for DMA) and A3640 3.1 (or you must change an IC on the CPU board)
Anyway . . .a good board for the SCSI II DMA controller too :-)
Ciao
-
Framiga : I thought I only needed to change those chips if I want to put 256 Mb on it ???!!! Think my 3640 is a 2.1 and the SB is 9 I think ...