990fxa-gd80 resume issue

Question

Hello, i hope someone among you good guys can help me with a very annoying issue i am experiencing in my system, that is driving me mad and that i could not solve in a month of tries. I own an HTPC based on the following configuration:
AMD Phenom II X4 945 CPU
MSI 990FXA-GD80 M/B
8Gb Corsair XMS3 DDR (2x4Gb)
Corsair AX-650 PSU
Samsung 256Gb 830 SATA SSD (2 partitions, system + data), AHCI SATA mode
Seagate 3Tb Barracuda SATA HDD with GPT table
ATI HD 5750 video card (2 displays attached)
Terratec Cinergy DVB-S2 card
Hauppauge HVR-2200 DVB-T card
Silverstone LC-16m case with Imon VFD + Imon Pad remote and USB card reader
Internal serial port, 1394 and eSATA ports enabled
Logitech USB Webcam, USB speakers and USB G110 illuminated keyboard
Toshiba laser mouse
Windows 7 x64 sp1, windows Media Center + DVBLink TV source, MST and various other programs.
Hibernation disabled
No overclok
I used this HTPC with much satisfaction from nearly 1 year, never experiencing an issue: i used to keep it in S3 mode 24/7 and it always got out from S3 state to record TV programs without any problem.
I installed the second drive, the 3Tb Seagate Barracuda, the first week of september. Then a day between the firsts of october i installed Mediaportal to give it a try; fearing system modifications by that software, i saved a backup image in my second drive. After a pair of days (or maybe at that time i noticed it for the first time), the issue has started.
The issue consists in a strange system freeze when the HTPC tries to wake up from S3: when the HTPC tries to exit S3 state the case led gets on, the HDD led blinks once or twice and then fans start running loudly and the HTPC freezes BEFORE the display can show any image (it remains black and goes to power saving mode) - power led on and HDD led off. No blue screen (the display is off). No memory dump. Keyboard's leds off. No manual crash dump possible. All i can do is keep power switch pressed until system complete shutdown.
But the really strange thing is that it happens ONLY once or twice a day, in the rest of the times the HTPC gets to wake up from S3 normally without any issue: it usually wakes up from S3 a number of times per day (7/8 minimum), but only 1/2 times the freeze issue happens (more often early in the morning or around twilight, seldom in other time slots)... Also, when on, the HTPC runs flawlessly as ever.
Thinking MP was guilty in some way, i restored the backup image but unfortunately the issue didn't disappear! So MP was no to blame... something different had happened to my PC...
I think you can understand that such an issue is really serious for an HTPC, because it makes it really untrustable for scheduled recording work: often recordings fail because of the HTPC freezing when it tries to resume... my wife is really sad about it...
Trying to solve the issue, i made the following:
running memtest and video card memory test - no error found
change nearly every MST options - no effect
reading carefully W7's event viewer logs after and between freezes - nothing found that could clarify the issue
changing all ACPI and power related BIOS options (C3 support, EUR 2013, CPU phases, DDR phases, shadowing, etc...) - no effect
updating BIOS and all drivers - no effect
disabling cool'n'quiet - no effect
unplugging Segate 3Tb HDD - no effect
unplugging all external and internal USB devices (except mouse) - no effect
uninstalling ATI video card and running with legacy drivers - no effect
disabling embedded Ethernet adapter - no effect
unplugging the second display (an HDTV) - no effect
tried to get a manual crash dump - not possible as when the issue happens the HTPC is freezed
Those tries took very long to be made, because every time i have to wait all day long for the issue to happen: it NEVER takes place if i wake up the HTPC after a few seconds sleep, seems like it needs at least a few hours of S3 state to take place.
Now, many particulars of the issue seem to lead to a compatibility problem between PSU and motherboard: i read about other users experiencing similar problems using high-end PSUs (min load related?), problems they solved by finding older or cheaper PSUs compatible with their MB (that's a blind try thing, luck was needed)... but in all cases PSU functioning was not bad, so no RMA was possible. Anyway, it is obvious that changing MB solved the issue as well... so Corsair support states it is not a PSU issue but a MB related one.
This seems to be a frequent problem for intel z68 based MBs, but i suspect my 990fxa MB can show the same compatibility issue with Corsair AX PSU, assuming some power related modification has happened in the last month in PSU or MB circuitry.
So i would like to know if someone else is/is not experiencing the same issue using same MB and PSU; more, i would like to know what 80+ PSU is SURELY working flawlessly with my MB, in case i should have to solve the issue by replacing the Corsair PSU (that is manufactured by Seasonic); finally, i would like to ask MSI technicians to verify the issue and possibly working around it with a BIOS update (maybe raising resume initial load, if PSU min load is to blame).
Thanks in advance.

Answer 1

Even with AMD power reduction, consumption while on is nearly ten times than in standby... it happens me to leave my PC in S3 for 3/4 days, so power consumption would be too much (i write from Italy and here AC current is much expensive!).
Anyway, i took a more accurate look around about PSU/MB incompatibility and i'm now sure enough that this is the problem. It seems certain MBs in power saving modes (like S3) require a too low power from PSU, so that PSU min load is not achieved, that makes it malfunction. This happens to new, energy efficient PSUs, that eliminate minimum load resistors to achieve maximum efficiency...
Look at this: http://www.silentpcreview.com/forums/viewtopic.php?t=58802.
So this issues happen because MB is too efficient (it requires too low power from PSU) and PSU is too efficient itself (it eliminates power used to remain above min load in power saving). Is this true? It seems ridicolous to me!!!!!!! To save a couple of watts we are forced to leave PC on so wasting dozens of watts? Are PC engineers really dummies?
BUT it looks like this can easily be solved by a BIOS adjustment, isn't it?