Expanding an A1200, advice

[jman]

Hello,

I may have found a fairly good deal for expanding a stock A1200:

1) Blizzard 1220/4 or GVP Jaws? Both 4mb. Specs would be favorable to the latter, but some reports in EAB say the performance difference is thin. Difference in price is not so thin :-\

2) Once you have either board or the other inside, do you have room also for a SD/FF too? Accelerator cards stay into the expansion bay, while the SD/FF stays on the other side of the M/B, correct?

Thanks, I'm slightly confused.

[cpiac64]

blizzard 1220 is an expansion, the gvp jaws is an accelerator and use a fast cpu

contact me in pm, i have more and various material for you.

[Djay]

i have a Blizzard mkIV 68030@50mhz with 64mb of ram (60ns)... giving a good performance on ADoom , trap door slot is back on and didnt touch the floppy drive... NO probs!

however.... drilled airholes in my trap door slot cover, just to vent heat... it gets Hot!

see my My Amiga! thread for my specs (link in sig)

[ajk]

2) Yes, generally all scandoublers are placed near the video circuitry, well away from the accelerator

[jman]

Another question that came up: I want to understand how FastRAM on accelerator cards and RTG cards is used, I think I have in my head a couple of possibly wrong assumptions and some doubts.

First of all RAM located on an accelerator card qualifies as *system* FastRAM, correct? A sort of multipurpose fast memory for any task - probably faster than Fast Ram located on the M/B because of lower latency, faster CAS timings and much closer to the accelerated CPU.
In this respect this fast memory works like RAM on the PC world, right?
If I have FastRAM on an accelerated card, what happens to the system FastRAM located on the M/B? Disabled?

How about RAM on an RTG card? Is that memory reserved for display purposes? Something like on modern graphic cards, more RAM equals higher resolutions and it's used as a framebuffer before sending the elaborated video pages to the display, correct?

Thanks for clarifying all the above.

[ajk]

There is no fast RAM on the A1200 motherboard, but for example on the A4000 it doesn't get disabled, but the priority is such that it will not be used unless all of the RAM on the accelerator is full.

RAM on "classic" graphics cards is indeed used for display related purposes only; though on some of the PCI busboards if you have a Radeon or such with lots of memory, in my understanding that can be used in part to extend the system RAM too. Not sure what the speed is like though in that case, likely much slower than the RAM on a good accelerator, similar to the DKB3128 or ZorRAM cards.

[zipper]

Originally Posted by ajk

RAM on "classic" graphics cards is indeed used for display related purposes only; though on some of the PCI busboards if you have a Radeon or such with lots of memory, in my understanding that can be used in part to extend the system RAM too. Not sure what the speed is like though in that case, likely much slower than the RAM on a good accelerator, similar to the DKB3128 or ZorRAM cards.

At least with Picasso RTG cards it was possible to use the RTG RAM as system RAM with some tweak - no bigger point as it was slow. Amiga OS is clever when using RAM, the fastest is always used first. On my A4000 there was 128 MB on CSPPC that was first used, then 16 MB on the mobo and then 4 MB 16bit RAM on Oktagon 2008. It was informative to fill all that RAM and to see the system crawling when the 16bit RAM came in use...

[jman]

Originally Posted by zipper

... and then 4 MB 16bit RAM on Oktagon 2008. It was informative to fill all that RAM and to see the system crawling when the 16bit RAM came in use...

Even the RAM on the HD board, I'm impressed.
I suppose that if you put also a couple of SIMM banks in the nearby of the machine you could see after a while ones and zeroes floating in the air to and from the A4000 :-)

[fgh]

Originally Posted by cpiac64

blizzard 1220 is an expansion, the gvp jaws is an accelerator

Blizzard 1220 is also an accellerator board, with its own 68EC020 at 28mHz.
It has 4MB and can be upgraded to 8MB with this extension.
(It should even be pcmcia friendly with 8mb)

68020 and 68030 perform similarly at the same frequency. GVP Jaws is faster at 40mHz, but the speed difference between them should not be huge. For 2d games I wouldn't bother, for 3d games and AGA demos there would be a slightly bigger difference.
GVP Jaws can have up to 32MB, but the special GVP RAM is rare and expensive.

If you want a machine to run WHDLoad 8mb fast gives you freedom to first work in workbench, then launch games and still have enough RAM for all AGA games. With 4mb fast some AGA games will require that you run the game without loading wb first. (boot w/o startup-sequence, boot into AGLaunch or similar)

Both chip ram and fast ram is 'system ram'. Chip ram can be accessed by CPU and amiga chipset (audio, video, etc), the fast ram only by the CPU.

[cpiac64]

thanks for more info fgh

[rkauer]

Originally Posted by fgh

Blizzard 1220 is also an accellerator board, with its own 68EC020 at 28mHz.
It has 4MB and can be upgraded to 8MB with this extension.
(It should even be pcmcia friendly with 8mb)<SNIP>

No way: the Blizzard 1220 maps its memory to Zorro 2 autoconfig space, ruling out the PCMCIA port when more than 4Mb is accessed.

[fgh]

Originally Posted by rkauer

No way: the Blizzard 1220 maps its memory to Zorro 2 autoconfig space

Ok I stand corrected.
(Just read two sales threads where sellers claimed it was pcmcia friendly)

My apologies for spreading lies

[jman]

Another thought about A1200 accelerators.

Provided same CPU and mostly same clockspeed, are they virtually all equal once fitted or there is a sensible performance gap between X and Y brand?

It also seems that some of them are picky with RAM or tend to overheat.
Is there a general accepted "rating" for these boards? Is there a brand that shall be excluded while searching for an upgrade?

Thanks

[rkauer]

Most, if not all, 030 accelerators do a boost from 5 to 9x of the non-accelerated A1200, pending the clock and maker.

My Microbotics 1230XA do a 7.8x (using 50ns 128Mb SIMM), but a Blizzard 1230mkIV tops to 9x faster. They both have 50MHz 030. Apollo 1230 is the second best accelerator (a bit behind the Blizzard), followed by many others.

Here you can check the performance of all 1200 accelerators:
http://amiga.resource.cx/perf/aibb.p...me&ref=mbx1230

[zipper]

Except the fastest "classic" 030 accelerator, ACT 1200xl is missing.