I like the nr 4 maybe you can use onboard usb controller and save a pci slot.

Well, I've got a Seagate ST336607LW too but also a Seagate ST318451LW, however your "Tenfold Screamer" seems to have an underperforming SCSI controller for that kind of disks.
Your Adaptec 2940UW does not support LVD SCSI, so you're stuck to 40 MB/s from SE (Single Ended) SCSI.
And you need a SE terminator too for your bus because a ST336607LW does not provide termination.

Instead I'd recommend you to use an Adaptec 19160 or 2940U2W.
If it is easier to find for you, you may try Adaptec 29160 or 29160LP too. Although they are PCI-X and your dual processor mainboard is not that cards run well in 32 bit PCI slots too.
However, you still need a twisted pair SCSI cable with a LVD terminator.

The cable I have on that SCSI controller has only three plugs. Two go into the Seagates and the third (a bit obvious) goes into the controller. Akin to a standard IDE cable, if you will.

As for finding LVD terminated cables and a different controller... no go unfortunately. Not that the drives I used might be any faster since they both are different speeds. The older and noisier drive (HDD2) is rated Ultra320, while the NOS drive used for HDD3 claims Ultra160 despite being the exact same model.

PcBytes wrote on 2024-08-04, 02:53:

The cable I have on that SCSI controller has only three plugs. Two go into the Seagates and the third (a bit obvious) goes into the controller. Akin to a standard IDE cable, if you will.

As for finding LVD terminated cables and a different controller... no go unfortunately. Not that the drives I used might be any faster since they both are different speeds. The older and noisier drive (HDD2) is rated Ultra320, while the NOS drive used for HDD3 claims Ultra160 despite being the exact same model.

Interesting. Can you post pictures of them please? (top + bottom side)

It is obviousely your controller terminates one side of the cable/bus.
But how do you terminate your SCSI cable at the drive side then?

If it has a terminator, may you post a picture of your SCSI cable please?

Disruptor wrote on 2024-08-04, 07:41:

Interesting. Can you post pictures of them please? (top + bottom side) […]
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PcBytes wrote on 2024-08-04, 02:53:

The cable I have on that SCSI controller has only three plugs. Two go into the Seagates and the third (a bit obvious) goes into the controller. Akin to a standard IDE cable, if you will.

As for finding LVD terminated cables and a different controller... no go unfortunately. Not that the drives I used might be any faster since they both are different speeds. The older and noisier drive (HDD2) is rated Ultra320, while the NOS drive used for HDD3 claims Ultra160 despite being the exact same model.

Interesting. Can you post pictures of them please? (top + bottom side)

It is obviousely your controller terminates one side of the cable/bus.
But how do you terminate your SCSI cable at the drive side then?

If it has a terminator, may you post a picture of your SCSI cable please?

Unfortunately this is the best picture I can give, since I currently don't have much access to the unit at the moment. But to explain it as short as possible - the same connector you see in the previous photo that goes into the controller is present on the hard drives side.

To further explain it, look at the cable down below. My cable's connectors are exactly similar to it, except the rest of the cable isn't coloured like DataPro's cable. It's plain white, reads IOI and has only two (three if you count the controller end) of those 68pin "channels".

So your Ultra (!) SCSI bus is unterminated at one end.

Although it's probably the same thing (one end is unterminated), I finally found a picture of the exact cable I use. The only small difference is mine has a IOI paper handle on the controller end.

Anyways, I'm not exactly seeing any slow operation or such. The drives seem fast enough as they are at the moment.

Fine, that's what I was looking for.
I hope the end connector of the connectors with the short distance has the termination then.

The Adaptec 2940U2W and above will tell you about termination faults, the 2940UW not.