The 2120S is a pure Raid card with a 64/66 PCI interface; not very flexible, and performance is not stellar.

The other Adaptec cards 29320 & 39320 are a hybrid HostRaid PCI-X controller card: Excellent cards.

The 29320 & 39320 cards can be changed, via Bios & to be a Raid or a regular SCSI controller; or both if you purchase the dual channel model (39320A-R)

To my knowledge the Windows x64 does not have native 64 bit Raid drivers, nor does the Adaptec website; I am sure the drivers will be available in the near future.

I currently have Windows 64 installed using the Adapted 39320A-R configured as a SCSI controller card, and the windows installation program has a native 64 bit drives that installs during Windows setup.

The native driver will work with the 29320 & 39320 Adaptec cards, as long as they are configured as SCSI controller cards, not Raids.

I believe no 64 bit drivers are available for the 2120S raid card.

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@Ian Hovell wrote:

I would like recommendations as to which Adaptec SCSI adapter to buy.

The models I have available to me are :

2120S OEM 128 MB

39320D-R

29320A-R

It must allow me to install windows xp x64 CR2

What is the real difference between these cards?

TIA

Ian

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Hi,
I'm new to this board so apologize if this issue has already been addressed.
Somewhere in the literature on a new 670 I think there is a statement that a 2nd scsi controller can't be added (in addition to the one on the mb) "for technical reasons."
I haven't tried, but am tempted to ;)

If true, that might be a factor in your choice

jim

Jim- I'm not a 670 owner yet, but I do have a 530 and 620s- on them you can disable the onboard

The 2120S is pure SCSI RAID card and it only operates at 64/66 MHz, detrimental performance since the 670 can handle 64/133 MHZ.

The other two are PCI-X compliant (64/133) they are a hybrid card: It can be configured as a HOST Raid (a Raid Controller) or the Raid can be disabled via a BIOS change and the card becomes a regular SCSI controller for JBOD.

There are multiple permutations of the Adaptec PCI-X Cards:

Adaptec SCSI RAID 2130SLP - 1-channel, 64/133 MHz, low-profile MD2 form factor for high-density pedestal and rackmount servers
Adaptec SCSI RAID 2230SLP - 2-channel, 64/133 MHz, low-profile MD2 form factor for high-density pedestal and rackmount servers
Adaptec SCSI Card 39320A-R - 2-channel, 64/133 MHz, full-height, half-length card with HostRAID™ RAID 0, 1, and 10
Adaptec SCSI Card 29320ALP-R - 1-channel, 64/133 MHz, low-profile, half-length card with HostRAID™ RAID 0, 1, and 10
Adaptec SCSI Card 29320A-R - 1-channel, 64/133 MHz, full-height, half-length card with HostRAID™ RAID 0, 1, and 10
Adaptec SCSI RAID 2020ZCR - 0-channel PCI-X SCSI RAID card that uses the Ultra320 SCSI chip on the motherboard.

As you can see the cards provide different capabilities. I prefer the 39320A-R since its dual channel inside & out. I can configure one channel as a RAID the other channel as a SCSI, or both as SCSI or RAID; you can see the flexibility. The PCI-X when working in dual channel will transfer at an aggregate of 640MB/sec.