ireland@ac.dal.ca (03/24/91)
Hi. I just read in the April MacWorld that one ought to put the larger capacity SIMMS in bank B on a IIci for maximum performance. I have a 5 meg IIci and haven't yet checked to see if I'm following this rule. Could someone explain the reasoning behind this. How much difference in speed is one likely to observe? Thanks, Keith Conover ireland@ac.dal.ca
long@mcntsh.enet.dec.com (Rich Long) (03/25/91)
In article <4140@ac.dal.ca>, ireland@ac.dal.ca writes... >[why should larger SIMMs go in Bank B of a IIci?] This is because of the built-in video. Memory for the video RAM comes out of Bank A, and this memory is also used for main memory. The CPU contends with the video controller for this memory, slowing performance somewhat. Therefore, the more memory that can be stuffed in Bank B, the better, since it will NOT be subject to this contention. You can minimize the performance hit by either 1) running the built-in video at a lower screen depth or 2) using a Nubus video card (which eliminates the problem). Richard C. Long * long@mcntsh.enet.dec.com * ...!decwrl!mcntsh.enet.dec.com!long * long%mcntsh.dec@decwrl.enet.dec.com
sethcohn@alchemy.tcnet.ithaca.ny.us (seth cohn) (03/25/91)
ireland@ac.dal.ca writes: > Hi. I just read in the April MacWorld that one ought to put > the larger capacity SIMMS in bank B on a IIci for maximum > performance. I have a 5 meg IIci and haven't yet checked to > see if I'm following this rule. Could someone explain the > reasoning behind this. How much difference in speed is one > likely to observe? Thanks, > > Keith Conover > ireland@ac.dal.ca Apple has tested this fully, and as I understand it: the Ci, due to the way it updated things, goes to bank A for certain refresh states, but if you have the BIG (ie 1 meg) simms there, then it will function "normally", whereas, with the SMALL simms (ie 256k) simms there, the BIG simms in bank B will not be slowed down. Apple claims up to 30% increase in speed. "CLAIMS" is the operative word here. Depends on what you're doing. I'd say that the minimal work involved in swapping banks is worth it, but don't feel like it's SUPER-vital, just a bit more speed for some things. Seth Seth Cohn, Service Tech. 607-273-2815 voice 607-272-7002 BBS All things posted are opinions by me, of me, for me, or to me. And another thing..........I'm not sure you're real.
corrie@serss0.fiu.edu (vaalpens) (03/25/91)
In article <4140@ac.dal.ca> ireland@ac.dal.ca writes: >Hi. I just read in the April MacWorld that one ought to put >the larger capacity SIMMS in bank B on a IIci for maximum >performance. I have a 5 meg IIci and haven't yet checked to >see if I'm following this rule. Could someone explain the >reasoning behind this. How much difference in speed is one >likely to observe? Thanks, > >Keith Conover >ireland@ac.dal.ca Keith, I remember reading a while back when the IIci-s came out that the reason for this was two-fold: 1- when using the built in monitor-card the IIci uses memory in bank A which tends to cause slow performance when using only the normal finder which places global variables in bank A as well. 2- Solution: using multifinder, globals are placed in Bank B, and the onboard video-card still uses bank A to store its stuff. Because of the memory management being used, you do not need to install memory quite restrictedly as you once had to, so you can decide how much memory should be used for the onboard video-card (Bank A), and how much is available for applications, globals, etc... (Bank B). At least that's what I remember about the article. You may want to look at MacUser/MacWorld issues around the time the IIci was actually released, or shortly thereafter. Corrie ------- -- Cornelius J. van der Merwe | Computer Support Specialist corrie@fiu.edu (internet) | UCS, Florida International University corrie@servax (bitnet) | Miami, Florida
fiddler@concertina.Eng.Sun.COM (Steve Hix) (03/26/91)
In article <4140@ac.dal.ca> ireland@ac.dal.ca writes: >Hi. I just read in the April MacWorld that one ought to put >the larger capacity SIMMS in bank B on a IIci for maximum >performance. I have a 5 meg IIci and haven't yet checked to >see if I'm following this rule. Could someone explain the >reasoning behind this. How much difference in speed is one >likely to observe? Thanks, One of the banks is used by the on-board video. If you're not using the builtin video port, it shouldn't make any difference, since RAM timing wouldn't be affected. -- ------------ The only drawback with morning is that it comes at such an inconvenient time of day. ------------