Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!snorkelwacker.mit.edu!paperboy!hsdndev!dartvax!Brian.V.Hughes From: Brian.V.Hughes@dartmouth.edu (Brian V. Hughes) Newsgroups: comp.sys.mac.hardware Subject: Re: The LC vs. IIsi (LONG) Message-ID: <1991Jun7.192453.11305@dartvax.dartmouth.edu> Date: 7 Jun 91 19:24:53 GMT References: <1991Jun5.175401.14345@sequent.com> Sender: news@dartvax.dartmouth.edu (The News Manager) Organization: Dartmouth College, Hanover, NH Lines: 135 In article <1991Jun5.175401.14345@sequent.com> lff@sequent.com (Lou Fernandez) writes: > I would like to buy a Mac for home use and am trying to decide what > model is appropriate. At this point, both the LC and IIsi seem like > viable choices and I am trying to determine whether the IIsi is worth > the extra $1K to me. Well, since you get a good deal more for that extra grand, you have to decide if you need it. > Today, my requirements are fairly modest. I expect to use the machine > primarily for spreadsheets, word processing, and home finance programs. > I will probably get a black&white monitor rather than color. My primary > concerns are for longevity and future expandability. There are some limitations with the LC and some spreadsheet and financial programs... See below... > I have some specific technical questions about the two Macs but I would > also appreciate a pointer to a good technical reference about the Mac > line which I could read to answer these and other questions. If these > are FAQ or the subject of recent discussions, a pointer to a > comp.sys.mac.* archive would be helpful. These should probably go into the FAQ list, and may already be there. I'm not sure.... > 1) Memory capacity > > As memory continues its drop in price, I believe future Mac software > will require much more of it. The literature says the LC is limited to > 10 Mbytes and the IIsi to 17 Mbytes. What are these limits based on? > Will they be different when 16 Mbyte SIMMs are available? How many SIMM > slots does each of these machine have and what are the speed > requirements? The LC comes with 2 MB soldered to the motherboard and 2 SIMM slots. These slots can accept either 256K, 512K, 1Meg, 2Meg, or 4Meg Low Profile SIMMS. You must install the same type of SIMM into both slots, there fore the actual Ram would be 2.5 Meg, 3 Meg, 4 Meg, 6 Meg, and 10 Meg respectively. I will not be possible to put 16 Meg SIMMS into an LC because there isn't enough clearance for the chip within the casing. As it, the 4 Meg Low profile SIMMs just barely fit into my LC. The IISi comes with 1 Meg soldered to the mother board and 4 SIMM slots that must be filed with the same type of SIMM. This is a function of the 68030 architecture. It only recognizes memory in banks of four. Becuase the LC is an 020 it can handle bakes of two. The IIsi can accept all ranges of SIMMs that the LC can handle plus 16 Meg SIMMs once they have been released. This would result in the following RAM configurations: 2 Meg, 3 Meg, 5 Meg, 9 Meg, 17 Meg, and 65 Meg with 16 Meg SIMMs. In terms of speed requirements, I wouldn't put anything slower that 80 Ns in any of the newer Macs. > 2) Video performance > > How do the LC and the IIsi differ in their built-in video support? Does > using the built-in video slow down the machine? Is there a black&white > mode which can be used to reduce this slowdown? The LC has the superior on board video capabilities, because the screen image is stored in a special Video Ram SIMM. The IISi stores the video image in physical RAM and can, when running in 256 color mode, cause certain functions to happen slower than normal. As with all Macs that have color, you can use the Monitors cdev to run in 1 bit (B&W) mode. It is also possible to upgrade the LC Video Ram from the stadard 256k SIMM to a 512K SIMM giving the same video performace that you have with a stock IISi, and if you have the 12" RGB monitor you will have 16 bit(32,000) color. > 3) Expansion slots > > Both the LC and the IIsi appear to have expansion slots of some sort but > how many and what kind? (Neither appears to be a Nubus slot.) Do you > think the expansion slot on the LC is a dead-end? The expansion slot confusion with the new macs is always an issue for novice mac users. the LC comes with a PDS (Processor Direct Slot) for its 68020, and there are cards slowly appearing for the LC by many 3rd partt vendors. The IIsi, when you first get it, comes with an adaptor slot that you must fill with a special adaptor card. This adaptor card comes in two versions: one is a Nubus adaptor the other is an 030 PDS adaptor (the same slot in the SE30). Both of the adaptor cards comes with a 16 mHz 68882 math co-processor, that will improve the speed of many functions, the most important of which is probably spreadsheet programs. > 4) Other functional differences > > I understand that the LC cannot support virtual memory. However, I can > buy LOTS of real memory for the price difference between the LC and the > IIsi. This could still be a problem if the LC has architectural limits > which prevent it from being able to access lots of real memory. It is possible to purchace an expansion card for the LC that contains both the PMMU chip for Virtual Memory, and a 16 mHz 68882 co-processor which the LC also lacks out of the box. With out the PMMU the LC is limited to 10 Mb of real memory. It is a lot of memory, but if you plan on doing any heavy CAD or full color DTP it can become a tight squeeze. > Are there other important functional differences between the LC and the > IIsi? Which of these might prevent some software which I buy in the > future from running on the LC? Functional differences... Well the IIsi, is a mac II the LC isn't. That ,means that you must use the on/off switch in the back to turn the LC off, instead of having shut down do all the work for you. Other than that the only other real difference is the fact that the LC is a 16 mHz 68020, and the IIsi is a 20 mHz 68030. There is a substantial performance difference between the two chips that goes beyond just the clock speeds. Hmm... just thought of another functional difference that the IIsi and the LC both share with respect to earlier Macs. The new mac all have a smaller power supply unit. What this means is there are limits to the size of hard drive you can put into one of them, because of the power needed to keep it running. The IIsi has an 80 Mbyte configuration, and now so does the LC(at least this summer it will), but i wouldn't recommed you put anything larger than an 80 Mbyte drive into one of them. There are also limits on the types of Nubus cards that you can put into a IIsi because of the power supply limitations, although fortunately most vendors are coming out with IIsi compatible versions of there more popular cards. > Thanks in advance for your insights into these questions and for any > other observations on the LC and IIsi which you feel are important. > > ...Lou -Hades hades@Eleazar.Dartmouth.Edu Dartmouth Medical School Macintosh Database Aministrator / Consultant