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PCI-Express and SCSI

Seagate Cheetah 15.5 drives most definitely saturate the PCI bus. Yes, just ONE. :Q

PCI-X and 8X PCI-E is where you will find most mid to higher end RAID controllers living.
 
Is there a reason to get one if I just have one u320 drive? And if so where can I get a semi good one for not so much money? Thanks.
 
i run adaptec 2940s all the time, and 2944s for my external enclosures (stupid HVD)... i also have very good luck with the qlogic equiv of the adaptec, but i dont recal the model they are all around 5-10 on ebay

and about pci bus saturation, yes my limiter is my bus, as its a 32bit bus, as when people compare speeds the generally use a 64bit pci bus to compare avalable bandwidth on...

im not sure on the actual speed on the 2940 compared to those newer ones in above links, as i only use scsi because i regularly have failing ide/sata drives (my record is 6 drives in 2 months dyeing, i have lost 1 scsi in 6 years)
 
Originally posted by: Dorkenstein
Is it crucial to have a SCSI controller that is PCi-E to get the most speed? Thanks.
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To get the most speed, even from ONE hard drive, you'll want either a PCI-Express adaptor or PCI-X (64-bit PCI as opposed to 32-bit PCI) adaptor. Many SCSI drives can easily attain burst speeds much faster than 32-bit PCI can handle. Not to mention the fact that any other device on a PCI slot will be fighting for bandwidth with your hard drive(s).

That's part of the problem with SCSI and non-server motherboards. Most of the SCSI adaptors are still made for PCI-X, and PCI-E adaptors aren't as common and cost a lot. But definately go for it if you have the money, PCI will be very limiting now and for any expandability should you decide to add more hard drives to the controller. PCI can't even handle two SCSI hard drives at sustained rates, let alone the burst speed of a single drive. This is one of the major reasons PCI-X and then later PCI-E were invented in the first place.
 
Originally posted by: MS Dawn
Seagate Cheetah 15.5 drives most definitely saturate the PCI bus. Yes, just ONE. :Q

PCI-X and 8X PCI-E is where you will find most mid to higher end RAID controllers living.
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QFT - my 15k.5 on a lsiu160 in a 32bit slot = 100MB/s burst and 95MB/s (holds about 95+MB/s for 80% of the drive, then drops to just ~80MB/s) str, so i would say this is definately saturating the 32bit pci bus since there are other items on that bus. drive can't even stretch its legs 🙂 looking for a pci-e 4/8x card or a c2d m/b (that also supports kentsfield - should last me quite some time if it supports quads - again kind of pricey) that has 64bit/133MHz pci-x slot since the pci-x cards are quite a bit cheaper than the pci-e ones.....

the 15k.4 or other new gens don't hit the max out the pci bus like the fujitsu max line - usually they are around 85MB/s str
 
Originally posted by: Dorkenstein
Can you link to a good PCI-X card? Really appreciate it.
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lsi and adaptec make good cards - some offer raid support too, personally i have used these 2 brands and have been happy with them. if you go to their sites - lsilogic.com and adaptec.com you can pick the one that has what you need. depending on your budget you may want to have a look on ebay for a better than retail deal, but be careful because sometimes people will sell you a adaptec card that is pulled from a dell workstation and thus be a little different than the true adaptec card - usually firmware.
 
Originally posted by: Dorkenstein
Are PCI-X slots rare? I don't know if my motherboard has one. I did find a nice SCSI card though.
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depends on the board - on a workstation or server board they are usually abundant, but with an enthusiast board they are more than likely no there.

unfortunatly i haven't found a 939 m/b with pci-x/133 but have found them in am2 and c2d flavors, but they m/b ran ~ $300 🙁

if anybody knows of a skt939 m/b with a pci-e 16x and pci-x/133 slot please let me know....
 
I picked up a reconditioned SCSI drive to put windows on, I am going to be running it on a socket 939 motherboard (I'm guessing 754 is bad?) pc that I am building. I'm just looking for a good card that will a) hopefully prevent bus saturation and b) not cost a limb.
 
Originally posted by: Dorkenstein
I picked up a reconditioned SCSI drive to put windows on, I am going to be running it on a socket 939 motherboard (I'm guessing 754 is bad?) pc that I am building. I'm just looking for a good card that will a) hopefully prevent bus saturation and b) not cost a limb.
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what drive did you get? basically anything lower than the brand new seagate 15k.5 will not saturate the 32bit pci bus and you can even run a u160 card since 32bit pci is ~133MB/s max and it has your lan on it too...can't remember if it has ide on it or if that has its own channel - which you can pick up for ~$30

even though i am running a 15k.5(got a excellent deal 😀) it really isn't maxing out the pci bus because i am running just 100Mb/s lan and i don't have anything that can write @ 100MB/s, just around 40-60MB/s which would be my other scsi and ide hdd. if i was writing to a sata raid 0 array i could then max out the pci bus

personally i would look for a lsiu160 or a adaptec 19160, 29160 or 39160 and enjoy the drive 🙂
 
either way - 15k.4 or 10k.4 you will be fine with a u160 card in a 32bit pci slot (the card will more than likely be a 64bit card, which is longer than a 32bit pci card, but quite a few of the 64bit cards work in a 32bit slot - verify this before you pick up a card but i use a lsiu160 in a 32bit slot so i know that one works. don't worry about a u320 card for that hdd especially since it is going in a 32bit slot. u320 is backward compatable with u160. is it a 68 or 80(sca-2) pin drive?

i have emailed lsi and asked them when they would make a u320 card for pci-e 4/8x and they said maybe q4 '06 or q1 '07, but most of their stuff is going toward sas (serial attached scsi - the cards can usually run a sas hdd which is a scsi hdd or sata hdds - best of both worlds and a nice way for manf to cut down on manf cost if all they need to do is build one card that takes care of many disciplines from corporate db server to cad/cam machine to videographer to enthusiast)
 
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