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From: meulenbr@cst.prl.philips.nl (Frans Meulenbroeks)
Newsgroups: comp.sys.atari.st
Subject: TT ram revisited
Message-ID: <meulenbr.676276267@cstw163>
Date: 7 Jun 91 06:31:07 GMT
Sender: news@prles2.prl.philips.nl
Lines: 29

Hi,

Thanks to all who responded on my TT ram question.
I won't summarize here. Allen Pratt dealt with the question in great 
detail. I don't think I should just duplicate that.

I'm left with a few small questions.

Allen says that in the future you can buy 16 MB of TT RAM
from atari. Could I do such an upgrade by myself by just
replacing the 1 MB simms by 4 MB ones, or are there other caveats?

Also I found out that the TT ram is 100ns ram. I do not have any 68030
doc handy, but with a 32 Mhz clock, I think at least one (and very maybe 2) 
wait states will be required to access this memory.
Would it be technically feasible to replace this memory with faster
memory, and get rid of this wait state? Will 80 ns be enough to get rid
of the wait state, or should 60 ns be used??

Since, if I'm not mistaken, the 68030 requires at least 3 clock cycles to
do a memory access. So removing a wait cycle would speed up the memory
access from 4 to 3 cycles. which would (in theory)  lead to a speed
gain of something like 25 %. Now of course not all cpu activity is 
memory access, so perhaps this figure is on the high side, but it seems
to me that a substantial gain could be obtained here.

--
Frans Meulenbroeks        (meulenbr@prl.philips.nl)
	Centre for Software Technology