> Date: Thu, 07 Nov 2002 00:32:15 -0500 > From: Charles Estabrooks <[EMAIL PROTECTED]> > > I am running an S900 with Sonnet G3/400 and OS 9.1. Historically, I > have > had memory issues and after delving into this list and the MacGurus > site, I > discovered the recommendation to avoid EDO RAM. Now here is my > experience. > When interleaved, the RAM fails TechTools RAM test, and the system > occasionally freezes at arbitrary times. When non-interleaved, it > seems to > work fine. > > Since I added RAM over the years, I have lost track of what I > purchased and > whether it was EDO or FPM. I currently have 320 MB (16MB built-in; > 64x4; > 16x2; 8x2). How can I determine if the RAM is EDO or FPM? I would > like to > add more RAM to this machine, but I'm hesitant until I solve this > little > mystery. Also, what is the largest DIMM I can use and the maximum the > S900 > can address? > > Thanks > > Charles
Which type of RAM to use in your machine has been one of the more controversial topics here over the years. I can tell you the MACGURUS web site does not recommend FPM ram for OLD WORLD machines. Someone may have said that on the Macgurus forum site but that is not the official word! Currently only the forums are available an the old info is only available through a back door. The site has been under construction so long it amazing. I quote from Macgurus. > Note: MacGurus reccomends the use of 168-pin, 5v EDO 64-bit, 2k > refresh, 60ns DIMMs in this machine. EDO DIMMs are engineered to > higher tolerances, and are more compatible with G3 processor upgrades. > The two types of RAM can be mixed in a machine. For more information, > please refer to the MacGurus RAM FAQ. > > a performance boost of approximately 5-15% results from installing > matching pairs of high-quality DIMMs in pairs, in corresponding slots > (A6-B6, A5-B5, A4-B4, etc.), as a consequence of interleaving. > > It should be noted that although Power Mac's ships with EDO DRAM > installed, the HammerHead ASIC memory controller treats EDO memory > like FPM, with the result that no performance benefit accrues. While > it is permissible to mix and match memory densities, speeds, and > chipsets when installing memory, MacGurus recommends continuity and > balance in all things, including memory configurations, and > consequently advises installing EDO memory in these machines in > matching pairs, unless repurposing DIMMs from other computers. > I have every reason to believe this was the best info available at the time of it's writing. However this was several years ago. Ram being sold new for our machines isn't at all the same type as it was then . Nearly all the ram being sold is Cheap PC 3.3 volt ram chips with a 5 volt convertor on the ram board so it will work in our machines. Now days it is much more important to buy ram that can be exchanged if it doesn't work then if it is FPM or EDO. A problem I had which maybe what you are having. I ran a mix of old ram interleaved which worked fine in OS 9.x and OSX when I upgraded to OS 10.2.1 I had all sorts of disk corruption problems. Several of my ram chips were marked as to FPM or EDO. I finally had the ram tested at a local ram shop. Interleaving FPM and EDO ram together was the cause of my problem. I'm now still using that ram but making sure the now marked chips are kept together with their own kind. Interleaving speeds things up more then I would have thought in our machines. http://www.chipmunk.nl/DRAM/DRAM.htm is a webpage that can help you identify your ram chips in many cases. Best of luck Will S -- SuperMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:supermacs@;mail.maclaunch.com> To unsubscribe, email: <mailto:supermacs-off@;mail.maclaunch.com> For digest mode, email: <mailto:supermacs-digest@;mail.maclaunch.com> Subscription questions: <mailto:listmom@;lemlists.com> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
