Samsung 32GB(impending failure flash cache RAID 0) / Hitachi 750 GB HD

The disk controller specs are usually found on the product page on the manufacturer's website. But it is not there on HP (common for HP). But I do recall a spec in there that gave the maximun spped as 1000mps - which is really slow. I'll look again to confirm.

It looks like HWinfo64 has the needed info:
For the Hitachi it lists: Drive Controller: Serial ATA 3Gb/s @ 3Gb/s
and ATA Transport Version Supported: SATA 2.6

For the Samsung it lists: Drive Controller: Serial ATA 6Gb/s @ 6Gb/s
and ATA Transport Version Supported: SATA 3.1

So the 2 hard drive bays are most likely on a SATA2 controller.

I believe the line item is showing the speed of the controller - not the speed of the drive connected to it.

The information on the RAID 0 for both drives is still confusing to me. I continue to hold to the requirement that says a RAID 0 can only be double the size of the smallest disk. I'm guessing that what you are seeing is a result of hard drive programs trying to make sense of this cache system baked into that HP workstation. Everything else I said regarding this hinges on that assumption.

I had seen the specs pages for that model days ago but I can't navigate back to it now. That HP website is driving me nuts!

Found this:
How To Tell the Storage Controller is SATA 2 or SATA 3 on Windows - NEXTOFWINDOWS.COM

You are correct about your options.

zbook said:

The current options appear to be:

a) continue using the computer as is and then troubleshooting if the flash cache fails
(I'm unsure whether this can or cannot be troubleshooted without reestablishing the RAID 0 with a replacement flash cache)

Yes, this may be your most logical option. If it ain't broke - don't fix it.
I would have a plan (one of the options below) ready to execute should the mSATA actually die. Maybe even buy the replacement module to have on hand if that's your first choice.

zbook said:

b) turn off the IRST using the acceleration off menu option
(I'm unsure whether this is a trouble free step or whether it may have HD boot problems)

I guess if you just don't want to replace the module this would be a logical option.

zbook said:

c) replace the flash cache with a refurbished cache

If you have faith in the HD SEntinal report and don't want to be bothered with a sudden and unexpected loss of use then yeah- that's going to keep things running as they are supposed to and eliminate the concern.
Note: I did see some new mSATA modules in those links that meet the specs.

zbook said:

d) replace the HD with a SSD
(this would have a fast boot but the controller read / write speeds are not yet known?)

Your spinner transfers at about 1000 mbps (on a good day, and an SSD on a SATA 2 controller will do about 3500, so maybe not as fast as the mSATA on SATA 3, but better than option (b).

All indications are that it is on a 3 Gb SATA 2 controller. Did you check the test in the link above?

Ultimately, it's your PC - you know how you use it and what you need from it. My opinion is meaningless.
(I'd be ripping it apart just to see how that system all works!)