Re: Looking for a 4Meg Ram card

[aa382@Freenet.carleton.ca (Marc Sira)]

In a previous article, henigan@quando.quantum.de (Kevin Henigan) says:

>I've thought about getting the new CVTech 4 Meg card that's expandable
>to 8 Megs. Any comments.
>
>A question about DMA and the GS.
>
>When I've got more than 4 Megs in my GS ( rom 01 ), then it's not DMA
>compatible anymore, but if I have a RAMFast rev D with then it is.
>
>Does this mean that >4Megs is a lot slower the 4Megs with a RAMFast Rev c?

I have the older (piggyback-able) CV-Tech card; I asked Drew about the >4MB
thing a while ago. He said that, in order to allow you 8 DMA Megs, the memory
card has to use something called a "code-locked loop" when accessing the
memory that lies over the normal DMA limit. Apparently this does result in
a small amount of slowdown, but not enough to be a pain or anything. If for
some reason you didn't want any slowdown at all, you could take over the
upper 4 Megs with a big RAM disk, though this would defeat the purpose of the
RAM card to some degree (/RAM5 starts at the top of memory, so none of the high
memory would get used by running programs).

This is assuming that the newer CV-RAM uses the same technique, of course.

I don't think it matters whether you have a Rev. C or D RamFAST unless you
have a RAM card that's entirely non-DMA (like my ugly old AE GS-RAM, ick).


-- 
Marc Sira                  |
aa382@freenet.carleton.ca  |  "Your god drinks...p-p-peach nectar."
toh@micor.ocunix.on.ca     '