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The Smart Response Technology (SRT) of a Intel Z68 can operate in two modes: Enhanced (Write-through) or Maximized (Write-back). Clearly, the Maximized mode sounds better since it will give you near SSD speed even with a relative small SSD.

The manual (Last two links on this page ) says the following about Maximized mode:

In this mode, cached data is written to the accelerated disk or volume at intervals to increase performance. If the cache device is reported as missing or failed and it contained data that had not yet been written to the accelerated disk or volume, then that data will be lost.

To me, this sounds like only when there is "dirty" data on the SSD cache and the SSD fails, data will be lost. A power outage will not cause any trouble since it will write them to the HDDs when the power is back.

However, a test by PC Perspective notes the following:

..I'd personally stick with enhanced mode unless I was extremely confident in the stability of my system (and had it connected to a good UPS).

So, does this mean SRT requires a uninterruptible power supply to prevent data loss?

Update #1

I have now talked to Intel support (using web chat) and this is the outcome:

Me: .... If I have an accelerated system using SRT and there is a power outage, will the ICH/Z68 write the outstanding data (that is still only on the SSD and not on the HD) write the outstanding blocks onto the HDD when the power returns? ...

Victor: Every device that will work as cache will loose the information on a power failure. In your case the data in the cache ( Solid-State Drive ) will be lost.

Me: ... Does this also mean I get a cache problem if Windows just crashes (but the power remains)? Would this also invalid all data inside the cache?

Victor: Correct, but the amount of data should not be that much, it will depend in the process that you are doing and the speed of your hard drives.

Me: Can you please give me a link or something where this is documented? ...

Victor: Unfortunately this information is not posted on the web site, but I will send your request up so that they add it. ....

Update #2

I also talked to the technical writer of the last Z68 test in the last c't - he is disagreeing with what the Intel Support said so they will now try to simply test it out. If I have new information, I will update again.

karel
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Tex Hex
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4 Answers4

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Seem to be a recomendation as opposed to a necessity but you may find issues arise without. From reading the discussion pointsin the comments in the discussion here:

And yes, a UPS is recommended as having a power outage while it's syncing a few MB of data would be pretty bad. For those folks, the Enhanced mode is probably recommended.

http://www.maximumpc.com/article/features/everything_you_need_know_about_intels_new_z68_chipset?page=0,1

I think the test by PC Perspective's notes say it well. In my experience typically it's servers that have a UPS, not that a single home/client PC couldn't have one especially without a server to backup to but again it just depends how far you want to go / budget / how valuable the data is.

To directly answer your question:

In enhanced mode no but in Maximized mode, to be absolutely sure, yes is the answer

Paul C
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Since yesterday I can answer this question myself: No, no data is lost.

While moving about 100 GB (10k+ files) from one partition to another (both on the accelerated array), the main power in my house went down. The file move was about 60% done at this time.

Upon restoring power and turning the computer back on, the Intel controller displayed the following during POST: POST image

Some lines are missing, but to me this looks like it has detected it has dirty data on the SSD and fixed it.

Checking the files on the new and the old location from my backup I could verify that no file was lost or damaged.

Tex Hex
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I don't have first-hand knowledge, but Intel Smart Response Technology Explained says :

The two different modes set up the SSD caching in different ways.

Enhanced mode is designed for maximum security, reducing the possibility of data loss but also limiting write speed as it writes data to the SSD and HDD at the same time.

Maximized mode is designed for optimum performance, writing data to the SSD and only periodically transferring it to the hard drive. This means that if anything should go wrong with the SSD, you could lose some data.

The outcome of an SSD failure would depend largely on what the SSD was caching at the time of failure, so it’s difficult to predict how it would affect your system.

It sounds like a power failure could lose the data from the hard-disk, but maybe not from the SSD (the emphasis is on "maybe").

harrymc
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I've been using SRT in Maximized mode for 3 years now (one of the benefits of answering a question so long after it's been asked...). I've yet to encounter any SRT-specific problems after power cuts, accidental unpluggings, unintended presses of the reset button, or blue screens, all of which I've had happen a number of times.

On the next reboot after an unanticipated stop, the computer runs through some kind of cache checking process (takes up to a minute, but usually less) and then goes on to the BIOS screen and then to boot Windows. It's my habit to then run CHKDSK, and most times it finds no problem - doesn't seem any better or worse than power cuts/etc. when using an ordinary hard drive really.

So overall I've found the system trustworthy. Of course, this hasn't stopped me keeping backups.

Tom Seddon
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