Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!helios!stat!aaron From: aaron@stat.tamu.edu (Aaron Hightower) Newsgroups: comp.sys.amiga.hardware Subject: Re: RAMs for the A3000 (also using DIPS and ZIPS both in fastmem) Keywords: ZIPs or SIPPs Message-ID: <16438@helios.TAMU.EDU> Date: 22 May 91 21:37:33 GMT References: <1991May17.170845.8740@informatik.uni-erlangen.de> Sender: usenet@helios.TAMU.EDU Organization: Texas A&M University Lines: 92 In article johns@dworkin.Amber.COM (John Silvia) writes: >> Could anyone please tell me, which RAMs are necessary to upgrade an >> A3000? Someone told me, that I need 1MB x 8 SIPPs and somebody else >> told me, that I need 1MBx1 ZIPs. Can anyone, who owns such a bugger >> look into the manual and send me a mail? > >There are two types of expansion ram for an A3000. There is PAGE MODE and >STATIC COLUMN mode. The Page Mode chips are 256X4, and the Static Column >chips are1024X4. 8 of either types of these chips are required for the >minimum memory expansion. Checking page 4-11 of the 3000 into manual reveals *4* types of memory. Your forgot the 256X4 Static Column and the 1Mx4 Page. In no way does static column identify the density of the chip. >Also, types of chips cannot be mixed in the same system. Either it's all >PAGE MODE or all STATIC COLUMN. True - also you cannot mix 256x4's with 1Mx4's. Remember that static column has nothing to do with density! Also, as I just proved to myself, I decided to leave my static column DIPS in their sockets and put two megs of FAST mem into ZIP banks 1 and 2 (leaving banks 0 and 3 open) and I now have a system with 3 megs of static column 256x4 RAM and 1meg of page-mode DIP CHIP ram. That is I have 1M DIP CHIP, 1M DIP FAST, 2M ZIP FAST. All of my fast memory is Static Column. It works great! >STATIC COLUMN chips offer more storage, and greater speed, and are more >expensive than PAGE MODE chips. Average Static Column pricing is around >$35-$42 per chip. STATIC COLUMN RAM allows faster reading of sequential memory. It is useful when you are using a CPU that has a CACHE and you want to burst in a section of memory into the CPU so that it can be executed without delay for memory refresh. Static column is only slightly more expensive than page mode, but 1Mx4 is about *twice* as expensive per megabyte as 256x4. Also, if you want to leave your current fast mem in place, you *must* buy 256x4. This is because you cannot put 1Mx4 ZIPS in while the 256x4 static column DIPS that come with the machine are also seated for use as fast mem. If you buy 1Mx4 you *must* move your DIPS from fast memory to CHIP memory. >It is highly suggested to buy only the STATIC COLUMN chips - SCRAMS allow >the Amiga to use it's fastest operation modes with a minimum of wait states >and such. > >The directions starting on page 4-13 of the "Introducing the Commodore Amiga >3000" manual explain this entire operation completly with all warnings that >should be heeded. > >I have heard that there are troubles with using the Page Mode chips but I >don't know what truth to trust them with. The Static Column chips are >better, faster and store more per chip. Again, I cannot emphasise enough how wrong this is - Static Column is a mode of operation - it has nothing to do with memory density!!! >For less than $300, you can get the 8 SCRAMS from a memory dealer, and they >install in less than an hour. The most important thing is the location of >the chips on the motherboard. Bank 0 must be filled first, and those >sockets are in a spread out pattern hiding with the other banks. Fill the >first sockets of each column, and then skip 3 sockets and put another chip >in. Repeat another two times, and set the jumper (J852) so that it connects >the rearmost pin and the one in front of it, and then you will have four >megs of ram. > >Also, remember that the first meg of fast ram must be moved from it's >sockets in front of the ZIP sockets, into the empty sockets on the opposite >side of the motherboard. These chips retire from fast ram to become the new >extra megabyte of CHIP ram. This MUST be done if updating the total memory >in the machine. There are no jumpers to set. Wrong again. I have a system right now with 1MEG of 256x4 DIP SCRAMS (that you are talking about) with 2MEG of 256x4 *ZIP* SCRAMS in banks 1 and 2. Page 4-10 of the manual states "The 8 DIP locations and the 8 lowest numbered ZIP locations are elctronically equivalent (both are bank 0). RAM chips can be installed in either the DIP section or the first bank of the ZIP section, but not both." In summary, if you buy Static Column 256x4 ZIPS, you can add up to 3 meg of ZIPS in banks 1, 2, and 3. There is no use in moving your static column 256x4 DIPS to CHIP when you could just put page mode in there anyway. The CHIP ram can't even take advantage of the Static Column feature anyway. >Mostly, in all of this, follow this one rule: RTFM - and things will be >okay. Before giving advice, maybe you should take it yourself. Later, Aaron Hightower PS: Check out my tetris game @ ab20:/incoming/amiga/yatc.lzh or ab20:/amiga/games/yatc.lzh depending...