Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!cmcl2!ccnysci!alexis
From: alexis@ccnysci.UUCP (Alexis Rosen)
Newsgroups: comp.sys.mac
Subject: Re: Mac memory speed confusion
Keywords: Memory speed, Cache memory, Wait states, Virtual Memory, Help
Message-ID: <1691@ccnysci.UUCP>
Date: 23 Apr 89 07:23:11 GMT
References: <7400@spool.cs.wisc.edu> <1572@ccnysci.UUCP> <21218@santra.UUCP>
Reply-To: alexis@ccnysci.UUCP (Alexis Rosen)
Organization: City College of New York
Lines: 34

In article <21218@santra.UUCP> jmunkki@kampi.UUCP (Juri Munkki) writes:
>I read that the IIcx has the CPU soldered to the motherboard. I hope
>this isn't true, since it would make adding a cache a lot harder and
>probably will cost you a new 68030.

Sadly, this is true. In fact, I don't think there's any way to get the 030
off of the board without destroying both. The 030 isn't just soldered- it's
surface-mounted, just like everything else (except, thankfully, the battery).
The justification is simple:
1) It cuts down on failure rates due to bad contacts (official reason)
2) It makes cheap third-party processor speed enhancements like caches
   impossible (real reason)

>Has anyone made a survey of video boards? Are there any affordable
>boards with an accelerator or faster RAM? When the Mac II was
>introduced, I intended to wait for DMA hard disk controllers and
>34010-based video cards.  The SCSI interface turned out to be fast
>enough, but it seems silly that the access time to the video RAM is
>300 ns (from the point of view of the processor).

The only board I know of with an accelerator is the RasterOps board (I
think it has an AMD QPDM on-board). It makes some things MUCH faster,
others not at all. Very expensive. On the other hand, there are now
three disk speedup products available (and we sure need them!).

If you really need fast video, wait for the Mac IIex, which has two
34020s onboard (I don't know how this works, but it seems to imply that
the video - at least the main screen - is interated onto the motherboard).
It should ship this summer (I hear August MacWorld, but June is possible).

---
Alexis Rosen
alexis@ccnysci.{uucp,bitnet}
alexis@rascal.ics.utexas.edu  (last resort)