> From: Alan Roberts <[EMAIL PROTECTED]> > Subject: Re: [PCI] Adaptec 2940UW > Date: Thu, 18 Aug 2005 22:36:45 -0400 > > Ok, finally tracked down info on the drive. It's an OEM version of the > Ultrastar 18XP. Various spec and installation files can be found here: > http://www.hitachigst.com/tech/techlib.nsf/products/Ultrastar_18XP > > It has only 1MB cache, so that can be a performance killer, especially > with multiple files. Under the media data rate it gives 92.2 to 179.2 > Mbits/s; divide by 8 (8 bits in a byte) and you get ~11.5 to 22.4 MB/s, > about average for a 7200RPM of that age. Keep in mind these rates are > generally for sustained transfers under ideal conditions. The reality > will tend towards the low end of that if not below the specs in most > real-world testing due to file fragmentation, OS efficiency and other > factors. You're probably getting most of the performance that drive is > ever going to provide. The hardware configuration should be fine as is, > since things are currently functional. > > The internal bus on the PCI PowerMacs is 10MB/s max, so you probably > get a slight boost in speed using the PCI card in some circumstances, > but you probably will not notice it. If you have no plans to get a new > drive in the near future, I'd suggest plugging the drive back into the > onboard SCSI and pull the card for now(so you can get your 3rd monitor > back. :) ). Just keep it in storage or something, since you may > want/need to upgrade to a better hard drive in the future; you'll be > considerably more impressed using it then. > > - Alan > > On Aug 18, 2005, at 6:50 PM, David Elmo wrote: >> Hi Alan, it is an IBM Type DGHS Comp IEC-950 12 Feb 98. 18G SCSI. And >> there >> are pins for the adaptor at the back and a set for the front. I have >> termination and autospin jumpered on the front and nothing on the >> back. It >> defaults to ID 0. True, the cable itself has active termination but >> when I >> tried with no termination jumper on the HD front, it was not happy... >> >> David Elmo
Thanks Robert, greatly appreciate this. You are reinforcing what I secretly want to do. Just by the way, I don't know how it happened (probably just used someone else's question subject) but although my original subject was UW, I started my q with "I am experimenting with an Adaptec 2940U2B SCSI card in a 7300 with a 405 MHz processor. I have an 18G IBM HD connected to ..." The point is my card is a U2B. But this probably makes little difference. What you say is consistent with the lack of noticeable improvement with other HDs and other SCSI card I have used: all probably down to the old and limited HDs I have... David Elmo -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; 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/pci-powermacs%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
