Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!bu-cs!dartvax!eleazar.dartmouth.edu!stevel From: stevel@eleazar.dartmouth.edu (Steve Ligett) Newsgroups: comp.sys.mac Subject: Re: How can I check SIMM speed? Message-ID: <15160@dartvax.Dartmouth.EDU> Date: 22 Aug 89 14:30:44 GMT References: <5880010@hpislx.HP.COM> Sender: news@dartvax.Dartmouth.EDU Reply-To: stevel@eleazar.dartmouth.edu (Steve Ligett) Organization: Dartmouth College, Hanover, NH Lines: 25 In article (well, I don't know what article really, it arrived and disappeared while I was on vacation) someone writes: >> How do I know someone didn't give me 150ns SIMMs either accidentally >> or because they figured I'd never know? > >Funny you should ask... > Look at the individual memory modules (chips) on the SIMM boards. Up >in the top right corner of the chips there should be a speed rating. "-15" >means 150ns. "-12" means 120ns. "-8", unsurprisingly is 80ns. These methods >of marking have been consistent with all of the SIMMs that I have seen, though >I am not certain that yours will have the same markings (but more likely than >not, I think). A better method is to check the back of the SIMM for a -15 or -12 or whatever. Manufacturers such as TI and Toshiba speed-test the SIMMs after assembling. A SIMM made of all 120 ns chips won't necessarily meet 120 ns specs. I've seen SIMMs with all 120 ns chips marked -15 on the back (and had them fail in testing that required 120 ns SIMMS), and I've seen SIMMs made with a mix of speed chips. A lot of "garage" operations (like mine), don't speed-test the SIMMs they make. I just buy faster chips than are needed (nowadays I only buy 80 ns chips). On a Mac Plus, 200 ns SIMMs would be fast enough. Steve Ligett steve.ligett@dartmouth.edu or (decvax harvard linus true)!dartvax!steve.ligett