jroutma: Adaptec are the kings of standard host adapters, but they're lagging a bit behind in the RAID controller segment. Here are the results of a round-up i saw lately (in a french mag):
* LSI Logic / MegaRAID Elite 1650 : best all-around, admin software not working with Linux (but the controller is working OK). Lots of very good options, great performance, etc. The only bad point is it scans the disk array after each configuration change.
* ICP Vortex / GDT 6523 RS : no RAID 3, good software, admin software working perfectly with Linux. Bad point = registry hacking is mandatory to get it to work (covered by user manual).

Mylex and Adaptec controllers finished last...
RAID is a different beast :p And i've seen many other reviews that lead to the same results -> it seems LSI Logic is the way to go. ICP Vortex use an Intel chip and seems quite good as well.
Besides, Adaptec boards are known to be very touchy about PCI clock settings.

The source article is here (put it in babelfish if you cannot read French...):
http://www.01net.com/rdn?oid=191763&rub=3345

Maybe you can help me gmat
What would be better, 4 used 9.1 g cheetah x15 for 600$ with a scsi card (which i don't need since i have an on board adaptec 39160) or 1 new cheatah x15 36lp 36g for 608 (plus taxes, around 700$)?
thank you

* If you plan to use software RAID, the quad 9.1G drives (1st-gen X15's, 2nd gen start @18 and 3rd gen @36) will outperform a single 36G drive. But at a price:
- heavy CPU load
- possible only with NT (and 2000, try to avoid XP...) or Unix / Linux
- lots (!!!) of noise. It will sound like a jet aircraft turbine (1st gen drives...)
- lots of heat (same reason)
- heavy PSU drain
- depending on your RAID level, reduced capacity (for example ~24GB with striping mirroring and parity)
If you can cope with that, and maybe pick up a RAID controller somewhere you'll live happily in SCSI-RAID land.

* If you plan to use them as 'standalone' drives, to get a total of 36GB you're better off getting that new X15 (it's a X15.3, right ?), by itself it's faster than any other drive, including previous generations of X15's.
- it's silent (3rd gen drive...)
- its blazingly fast
- it's slim (only 1 drive to fit..)
- it wont kill your PSU
- its rather cold (for a 15K HDD...)
Besides you've already got the adaptec board.

To me the choice is rather clear: get that X15.3 :)

nope, it would be a 2nd gen, 3rd gen still are not on the market in canada.
For the PSU, well it's currently powering 2 athlon 1ghz, with 3 ide hdd 7200rpm and 3 SCSI 7200 rpm (full height) with the hardware raid card. I won't use the hardware raid card on the 4 hdd (if i buy them) because it's really an old model (40mb/s per channel, 3 channel with only 4 megs of cache)

In case some of you missed it...

here's a link to the SR thread about using SCSI with WinXP

MS sucks! (like we don't know that...)

GMAT
Isn't the size of the X15 series more like
first gen: 4.3 , 9.1 and 18
second gen: 9.1 , 18 and 36
third gen: 18, 36 and 73
So a 9.1 could be a fisrt or second but not 3rd gen.

Nope. 1st gen had 9GB per platter, 2nd gen 18GB and 3rd gen have 36GB per platter bringing the biggest at 144GB (and ~$970 ...)
2nd gen are X15-36ES drives and they come in 18,36 or 72GB flavors.
They all have a 5 year warranty.
BTW 3rd gen (X15.3) is just around the corner... prices have been announced, and 1st-tier reserved models are out. They should show up quite soon.

isn't it the 10k.6 that goes up to 144g
I just checked on the seagate web site and the 15k.3 goes only to 73g. The size for the 15k.3 are 18, 36 and 73. The 10k.6 goes from 36 to 144
seagate web page for the mainstream server

Mmhh my wrong then. But i'm sure the 2nd gen does not exist in 9GB - i've never seen it anywhere with that size. The only versions of X15-36LP (not ES, ES was the 10k) i'm aware of are 18GB and 36GB. I thought they would have taken the same path as their 10K line...

Here's what I found, from SR:
Seagate Cheetah 15k3
ST318453LW/LC 18 GB
ST336753LW/LC 36 GB
ST373453LW/LC 73 GB

Seagate Cheetah X15-36LP
ST318452LW 18.4 GB
ST336752LW 36.7 GB

Seagate Cheetah 10k6
ST336607LW/LC 36 GB
ST373307LW/LC 73 GB
ST3146807LW/LC 146 GB

Seagate Cheetah 36ES
ST318406LW 18 GB
ST336706LW 36 GB

Maxtor Atlas 10k3
KW018L2 18 GB
KW036L4 36 GB
KW073L8 73 GB

In order of (personal) preference, I'd put them in this order:
1-Seagate Cheetah 15k3
2-Seagate Cheetah 10k6
3-Seagate Cheetah X15-36LP
4-Maxtor Atlas 10k3
5-Seagate Cheetah 36ES

(never mind what I posted earlier)

This does not include the Maxtor 10k4, since it hasn't been reviewed yet.

GMAT
It seems that you are correct in your info. From the information I was able to gather on the seagate website, there has never been a 4.3g first gen nor a 9.1g 2nd gen. It seems the 3rd gen is the only one to have 3 different models of hard drive.
So it would be more of my mistake than yours for the 1st and second gen.
Sorry

n/p dude. Have fun with your 15K.3 :) lucky man.