mkant@a.gp.cs.cmu.edu (Mark Kantrowitz) (02/13/90)
This article summarizes the replies to my question about speed and other factors for SIMMS for each of the Macintosh machines. Thanks to clarson@ux.acs.umn.edu, meuchen@grad1.cis.upenn.edu (Paul Eric Menchen), gbc@med.unc.edu (Geoff Crooks), craigm@wwu.edu (Craig McDonald), and jdevoto@apple.com (Jeanne A. E. Devoto). It was interesting to note that each gave me different information. This summary represents what I believe is the correct information. The definitive source is Apple's Tech Note 176, which is available in BinHex 4.0 form from apple.com or sumex-aim.stanford.edu via FTP. You will need Stuffit or BinHex4.0 to convert the files from Hex. Send comments/corrections/suggestions to mkant@cs.cmu.edu [1] Chip Speed: o Minimum speeds for various machines: - Mac+ 150ns in banks of 2 (max 4MB) - Mac SE 150ns in banks of 2 (max 4MB) - Mac SE/30 120ns in banks of 2 (max 4MB) - Mac II 120ns in banks of 4 (max 8MB) - Mac IIx 120ns in banks of 4 (max 8MB) - Mac IIcx 120ns in banks of 4 (max 8MB) - Mac IIci 80ns in banks of 4 (max 8MB) o All will run with faster chips. o A faster speed will not help performance, as wait states are hardwired. [2] Chip Types: o The IIci requires FPM (Fast Page Mode) chips. o In the SE, DIP SIMMs may not leave enough room for some expansion cards. o Different speed chips may be mixed, as memory access is synchronous. o Either 1x8 and 1x9 SIMMs may be used; the parity chip is ignored in the standard Macintosh line. [3] Chip Configurations: o In a given bank, the same density chips (256K SIMMs Or 1MB SIMMs) must be used. o So the following memory configurations work for a Mac+: Bank 1 Bank 2 Total Memory 2 256K ------ 512K 2 256K 2 256K 1MB (standard configuration) 2 1MB ------ 2MB 2 1MB 2 256K 2.5MB 2 1MB 2 1MB 4MB o For a Mac SE, swap banks 1 & 2 (this only matters in the 512K and 2MB cases). o For a Mac II, IIcx, and SE/30, you must upgrade memory in 4 SIMM chucks, so only the following configurations are possible: Bank A Bank B Total Memory 4 256K ------ 1MB 4 256K 4 256K 2MB 4 1MB ------ 4MB 4 1MB 4 256K 5MB 4 1MB 4 1MB 8MB Note that on the II, IIcx, and SE/30 there are no resistors to cut. The larger chips must be in the left bank. o The IIci isn't as picky about which bank you put the memory in (you can swap A & B), but there must be memory in Bank A if you use the on-board video. o For 4MB or 8MB SIMMs, you may have to wait either for future versions of the Mac II, or for SIMM manufacturers to include a PAL that intercepts certain Mac II signals that cause the SIMMs to go into test mode (thereby becoming very forgetful). [4] Where to get cheap chips: o The following two companies were recommended. People said that they sell 70ns or 80ns SIMMs for less than what most other places charge for 120ns chips. The phone number for Chip Merchant is from 800 information; no 800 number was listed for Technology Works. Both companies advertise in MacWorld, apparently. - Chip Merchant 1-800-426-6375 - Technology Works o Best price I've heard mentioned is ~$69/meg. --mkant
mkant@a.gp.cs.cmu.edu (Mark Kantrowitz) (02/14/90)
This is an update. I've corrected a typo (SE/30's take up to 8mb), and added a list of several dozen chip sellers with today's quote. --- This article summarizes the replies to my question about speed and other factors for SIMMS for each of the Macintosh machines. Thanks to clarson@ux.acs.umn.edu, meuchen@grad1.cis.upenn.edu (Paul Eric Menchen), gbc@med.unc.edu (Geoff Crooks), craigm@wwu.edu (Craig McDonald), and jdevoto@apple.com (Jeanne A. E. Devoto). It was interesting to note that each gave me different information. This summary represents what I believe is the correct information. The definitive source is Apple's Tech Note 176, which is available in BinHex 4.0 form from apple.com or sumex-aim.stanford.edu via FTP. You will need Stuffit or BinHex4.0 to convert the files from Hex. This information is provided AS IS and no warranty is made as to correctness or quality. Use at your own risk. Send comments/corrections/suggestions to mkant@cs.cmu.edu [1] Chip Speed: o Minimum speeds for various machines: - Mac+ 150ns in banks of 2 (max 4MB) - Mac SE 150ns in banks of 2 (max 4MB) - Mac SE/30 120ns in banks of 4 (max 8MB) - Mac II 120ns in banks of 4 (max 8MB) - Mac IIx 120ns in banks of 4 (max 8MB) - Mac IIcx 120ns in banks of 4 (max 8MB) - Mac IIci 80ns in banks of 4 (max 8MB) o All will run with faster chips. o A faster speed will not help performance, as wait states are hardwired. [2] Chip Types: o The IIci requires FPM (Fast Page Mode) chips. o There are two main types of SIMMs: Dual In-Line Package (DIP) SIMMs are taller than surface-mount (Low Profile) SIMMs. In the SE, DIP SIMMs may not leave enough room for some expansion cards. o Different speed chips may be mixed, as memory access is synchronous. Use the same speed chips in a given bank, however. o The part number on top of the chip should end with a two-digit number that indicates the speed. o Either 1x8 and 1x9 SIMMs may be used; the parity chip is ignored in the standard Macintosh line. [3] Chip Configurations: o In a given bank, the same density chips (256K SIMMs Or 1MB SIMMs) must be used. o So the following memory configurations work for a Mac+: Bank 1 Bank 2 Total Memory 2 256K ------ 512K 2 256K 2 256K 1MB (standard configuration) 2 1MB ------ 2MB 2 1MB 2 256K 2.5MB 2 1MB 2 1MB 4MB o For a Mac SE, swap banks 1 & 2 (this only matters in the 512K and 2MB cases). o For a Mac II, IIcx, and SE/30, you must upgrade memory in 4 SIMM chucks, so only the following configurations are possible: Bank A Bank B Total Memory 4 256K ------ 1MB 4 256K 4 256K 2MB 4 1MB ------ 4MB 4 1MB 4 256K 5MB 4 1MB 4 1MB 8MB Note that on the II, IIcx, and SE/30 there are no resistors to cut. The larger chips must be in the left bank. o The IIci isn't as picky about which bank you put the memory in (you can swap A & B), but there must be memory in Bank A if you use the on-board video. o For 4MB or 8MB SIMMs, you may have to wait either for future versions of the Mac II, or for SIMM manufacturers to include a PAL that intercepts certain Mac II signals that cause the SIMMs to go into test mode (thereby becoming very forgetful). [4] Where to get cheap chips: o People recommended the Chip Merchant and Technology works. o Phone numbers and today's prices for several chips sellers following. Prices are for 1MB 80ns SIMMs, except where noted. For companies that sell only in lots of 2MB, the price has been divided by 2. Only companies with toll free numbers are listed. "no-answer" means either busy signal or rang for 1 minute. o The cheapest price listed is $65; the most expensive $109. Allegiance Group 1-800-726-7466 85.00 American Micro Distr. 1-800-243-6654 99.00 Computer Care 1-800-950-2273 99.00 Data Memory Systems 1-800-662-SIMM 74.00 Delta Research Labs 1-800-999-1593 no-answer Dove Computer 1-800-622-7627 wholesale only Dr. Mac 1-800-825-6227 79.00 (70 ns) Hardware House 1-800-726-4622 74.00 Kelly Micro Systems 1-800-350-3900 70.00 MacConnection 1-800-334-4444 89.00 Dove Tool Kit 15.00 Dove MacSnap 2S 209.00 Dove MacSnap 4S 409.00 Mac Discount Warehouse 1-800-233-4426 too many switchboards MacLand 1-800-333-3353 84.50 Sold in pairs only. MacProducts USA 1-800-MAC-DISK 89.00 MacTel Technology 1-800-950-8411 72.00 MacWarehouse 1-800-255-6227 109.00 Memory Masters 1-800-726-2897 99.00 Micro Electronic Tech. 1-800-766-7466 salesperson will call back Micron Technology 1-800-642-7661 97.50 Sold in pairs only. Microtech International 1-800-325-1895 no-answer Mirror Technologies 1-800-654-5294 99.00 Newer Technology 1-800-678-DRAM 80.00 Peripheral Outlet 1-800-332-6581 65.00 Pinnacle Sales I. (PSI) 1-800-622-1722 80.00 Programs Plus 1-800-832-3201 no-answer Shecom Computers 1-800-366-4433 76.00 South Coast Electronics 1-800-289-8801 75.00 Technology Works 1-800-622-2210 87.50 Free installation kits w/purchase The Chip Merchant 1-800-426-6375 no-answer Third Wave Computing 1-800-284-0486 69.00 Turbo Technologies 1-800-542-7466 79.00