ASUS P8Z77-V Pro: instability caused by SENSOR.DLL in AI Suite II

Recently finished upgrading one of my desktop machines to a new ASUS P8Z77-V Pro board, along with a new Intel i5-3350p (no graphics) 3.1Ghz CPU and new 8GB of Patriot Gamer-2 PC3-1600 memory.

The rebuild also included two new super-silent Noctua NF-P12 PWM case fans, and a new Noctua NH-U12P cooler (which includes with two super-silent NF-P12 fans arranged in a "push/pull" arrangement on either side of the heat sink).

I also upgraded two of the four hard drives in the machine from older 3.0Gb/s SATA-II drives to new 6.0Gb/s SATA-III drives. One of these new SATA-III drives is a 250GB Western Digital Velociraptor where the OS partition resides, and the other is a 2.0TB WD 7200rpm Caviar Black drive for use with Windows Media Center use for \My Recordings. I'm not ready to go SSD yet, but probably will someday.

The rest of the machine is retained from the original, in particular retaining (a) Hauppauge HVR-2250 OTA/ATSC TV tuner card, and (b) Ceton InfiniTV 4-tuner cablecard-enabled TV tuner card.

Anyway, I've been working over the past few weeks to try and "stabilize things". I cannot tolerate any problems with the machine at all as it is also my whole-home HTPC/DVR and is on 24/7. When I'm out of town I need to have it 100% reliable doing its TV recording job.


First thing I tweaked early on was to disable the "ANTI-SURGE SUPPORT" option in the BIOS. I've never had any problem with the Nesteq ECS6001 (600W) PSU I'm still using in the rebuilt machine, but apparently it must be producing occasional "voltage spikes" that triggered the BIOS anti-surge functionality to literally power off the machine IN A HEARTBEAT!!

You can imagine my stunned alarm when I'm busy working at the machine and suddenly the whole thing instantly powers off by itself!! Not expected, and certainly not wanted.

After a bit of research into what did occur or might have occurred, I decided to disable this anti-surge support feature. I don't know if this was foolish, and I really should have replaced the power supply (which I didn't want to do because of all the internal cable hiding that's reflected in my build), but I simply took that option. This "instant power-off" response seems far too extreme.


However the real "instability" I've observed, and which I now seem to have "cured", seems tied to the sensor and hardware monitoring functions present in the ASUS "AI Suite II" software package which I installed. I really just wanted the EPU component (which controls voltages and fan speeds based on need and conditions), but I decided to install a number of the other available features as well to see what they looked like and did.

In particular, the package includes monitoring and display functionality that really is a duplicate of the Aida64 hardware monitor software I use. So I really had no intention of permanently opening the ASUS Probe-II equivalent, or actually using the SENSOR function in Tools. But I was still curious to see what they did and what they looked like.

Well, I've had continued anomalies and instability which I now feel to be absolutely related to this monitoring functionality in AI Suite II, and in particular SENSOR.DLL. I've had popup diagnostic error messages describing "access violation in SENSOR.DLL at...", I've had machine self power-off's for no reason other than that I was watching a recorded TV program, I've had sudden freeze/lockups watching a TV program on an extender/HDTV around the house, etc.

Now the freeze/lockups watching TV on an extender/HDTV is not something I've never seen before. But I had taken hardware steps to solve that... fewer power cable splits going to the hard drives, newer faster larger hard drives with much larger cache, etc... and I had achieved "stability" with the old machine. But for some reason, these same symptoms have now returned with the new machine despite it's much stronger capability.


Well, my "solution" has been to DISABLE THE SENSOR AND MONITOR FUNCTIONALITY OF AI SUITE II. In other words, you can customize AI Suite II with its "Settings", and I have unchecked these items.

Presumably, this has resulted in the deactivation of SENSOR.DLL.

And this has also resulted in STABILITY ON THE MACHINE!!!

Since un-checking SENSOR in AI Suite II I have not had a recurrence of either (a) auto self-power-off for no reason, or (b) lockup/freeze of an extender/HDTV while watching a TV program.


Obviously, in my opinion there is some software problem with the Sensor functionality, and in particular in SENSOR.DLL. Since I already use Aida64 anyway for my hardware monitoring I truly have no need for the duplicate (and less extensive) Sensor and display functionality of SENSOR in AI Suite II.

Of course there's always the possibility of a conflict of functionality between what Aida64 is doing and what SENSOR.DLL is doing that might be responsible for my symptoms, but I really have no way of knowing. It does seem unlikely, however.

Nevertheless, I've now looked at the various features of AI Suite II, tried it, and decided I will never use it and really have no use for it. So SENSOR is installed but I can un-check it in Settings to disable it... and in particular to disable SENSOR.DLL, which appears to be the root cause of all my hardware instability symptoms.

And that's what I've done... DISABLE SENSOR.

Just sharing this finding with everyone who might be going to this new family of boards from ASUS and installing the AI Suite II software as I did.

I also have an ASUS P5Q3 board (which I love) with LGA775 socket and Core2 Duo CPU in it.

And I have gotten addicted to having that EPU-6 software (which is what they used to call that component, which is now in AI Suite) manage voltages and fan speeds through the ASUS software and BIOS support.

EPU is also in AI Suite for the new P8Z77 board, which was the primary function I wanted to install the software. I disabled much of the rest of it, but did keep these sensor and monitoring components which now turn out to be problematic for stability (at least on my configuration).

Interestingly, when EPU-6 was by itself there was a small icon displayed in the System Tray that indicated visually (with a varying icon) the relative level of power-saving going on at any moment. With EPU in AI Suite they've done away with that dynamic, unfortunately. I miss it.

Anyway, even if I turned off everything else in AI Suite, I would absolutely still keep EPU to control all the voltages and fan speeds.