At 22:36 -0500 04/23/2002, Stephen Bright wrote: >Velocity now has $18.95 128MB Ram: > ><http://www.velocityupgrades.com/index.asp?cat=promo2> > >However, I don't recommend a single stick, even at that price. I'm finding >that all my VU ram that passed 5,000 iterations of RAMometer last summer is >starting to fail. I'd recommend everybody who bought VU Ram last year to >retest, as I have at least 2 dimms that originally tested good that are now >testing bad.
Hmmm. One possible cause of this is the IO voltages on the sticks. Velocity (and OWC) apparently builds the cheap stuff with 3.3V chips and our machines supply 5 V to the DIMMs. However, they put little voltage regulators on the DIMMs to step the supply voltage down from 5V to 3.3V. So far, so good. The problem is that the signal lines may also be using 5V on our machines and the chips are probably built for 3.3V signals. So the inputs that come to the DIMMs on the address and data busses are swinging 0 - 5V and the chips are built for 3.3V. I'm not certain this is the case. As the PPC IO lines run at lower than 5V and some 3.3V chips are designed to tolerate 5V IO, so I could be wrong, but I think this is a decent hypothesis. Jeff Walther -- 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! | SPECIAL SM LIST PRICES - 24x Bootable SCSI CDROM $39.99, Umax Processors $19.99 PowerSupplies from C500/C600 $49.99 J700/S900 $79.99 <mailto:[EMAIL PROTECTED]> Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
