Drop-outs in audio and high DPC latency for iaStor.sys

[Daniel1]

Hi, My X220 suffers two- fold
- audio drop-outs
- sluggishness for 5 minutes, when resuming from stand-by or hibernation
How to fix this?
So far, I have found
- high DPC routine execution time ((µs): 87252) in iaStor.sys, see below,
- high (>10%) CPU load from interrupts, quite high (>20%) CPU load from MCSHIELD.exe
- iaStor.sys version (10.1.0.1008)

Thanks
Daniel

Here, the Latency mon report
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CONCLUSION
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Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines belonging to a driver running in your system appear to be executing for too long.
LatencyMon has been analyzing your system for 0:00:23 (h:mm:ss)


_________________________________________________________________________________________________________
System Information
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Computer name: xxxxxx
OS version: Windows 7 Service Pack 1, 6.1, build: 7601
CPU: GenuineIntel Intel(R) Core(TM) i5-2540M CPU @ 2.60GHz
Logical processors: 4
RAM: 8467451904 total
VM: 2147352576, free: 1996070912


_________________________________________________________________________________________________________
CPU SPEED
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Reported CPU speed: 2591 MHz
Measured CPU speed: 473 MHz

Note: reported execution times may be calculated based on a fixed reported CPU speed. Disable variable speed settings like Intel Speed Step and AMD Cool N Quiet in the BIOS setup for more accurate results.

WARNING: the CPU speed that was measured is only a fraction of the CPU speed reported. Your CPUs may be throttled back due to variable speed settings and thermal issues. It is suggested that you run a utility which reports your actual CPU frequency and temperature.



_________________________________________________________________________________________________________
MEASURED KERNEL TIMER LATENCIES
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Highest measured kernel timer latency (µs): 90849.1427


_________________________________________________________________________________________________________
MEASURED SMIs AND CPU STALLS
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Highest measured SMI routine or CPU stall (µs) 11.6290


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REPORTED DPCs
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Highest DPC routine execution time (µs): 87252.6130
Driver with highest DPC routine execution time: iaStor.sys - Intel Rapid Storage Technology driver - x64, Intel Corporation

Highest reported total DPC routine time (%): 24.7220
Driver with highest DPC total execution time: iaStor.sys - Intel Rapid Storage Technology driver - x64, Intel Corporation

Total time spent in DPCs (%) 24.5963

DPC count (execution time <250 µs): 35978
DPC count (execution time 250-500 µs): 0
DPC count (execution time 500-999 µs): 686
DPC count (execution time 1000-1999 µs): 96
DPC count (execution time 2000-3999 µs): 31
DPC count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED ISRs
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Highest ISR routine execution time (µs): 58.8888
Driver with highest ISR routine execution time: i8042prt.sys - i8042 Port Driver, Microsoft Corporation

Highest reported total ISR routine time (%): 0.6800
Driver with highest ISR total time: hal.dll - Hardware Abstraction Layer DLL, Microsoft Corporation

Total time spent in ISRs (%) 0.1538

ISR count (execution time <250 µs): 43196
ISR count (execution time 250-500 µs): 0
ISR count (execution time 500-999 µs): 0
ISR count (execution time 1000-1999 µs): 0
ISR count (execution time 2000-3999 µs): 0
ISR count (execution time >=4000 µs): 0


_________________________________________________________________________________________________________
REPORTED HARD PAGEFAULTS
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Process with highest pagefault count: none

Total number of hard pagefaults 2
Hard pagefault count of hardest hit process: 1
Highest hard pagefault resolution time (µs): 22.9293
Total time spent in hard pagefaults (%): 0.0000
TODO: Number of processes hit: 0


_________________________________________________________________________________________________________
PER CPU DATA
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CPU 0 ISR count: 43196
CPU 0 ISR highest execution time: 58.8888
CPU 0 ISR total execution time: 146583.4693
CPU 0 DPC count: 35198
CPU 0 DPC highest execution time: 87252.6130
CPU 0 DPC total execution time: 23420545.6495
_________________________________________________________________________________________________________
CPU 1 ISR count: 0
CPU 1 ISR highest execution time: 0.0000
CPU 1 ISR total execution time: 0.0000
CPU 1 DPC count: 664
CPU 1 DPC highest execution time: 310.4320
CPU 1 DPC total execution time: 4180.4808
_________________________________________________________________________________________________________
CPU 2 ISR count: 0
CPU 2 ISR highest execution time: 0.0000
CPU 2 ISR total execution time: 0.0000
CPU 2 DPC count: 923
CPU 2 DPC highest execution time: 113.8892
CPU 2 DPC total execution time: 8530.6943
_________________________________________________________________________________________________________
CPU 3 ISR count: 0
CPU 3 ISR highest execution time: 0.0000
CPU 3 ISR total execution time: 0.0000
CPU 3 DPC count: 614
CPU 3 DPC highest execution time: 65.8128
CPU 3 DPC total execution time: 4155.1130
_________________________________________________________________________________________________________

[twistero]

Well, since iastor.sys belongs to Intel Matrix Storage, you can try uninstalling that...?

[Daniel1]

IASTOR.sys is an IDE ATA/ATAPI controller. It is named Intel(R) Mobile Express Chipset SATA AHCI Controller.
There is no option to disable the device.
Uninstall option I have found. But, it is ineffective.
Am I right, this is required for driving the disk?

[twistero]

iastor.sys is part of Intel's own ATA controller driver. It's not part of windows; in fact, the plain vanilla ATA controller driver from windows 7 is called atapi.sys. At some point you have installed Intel's driver, and it's now messing up.

Go to Control Panel - Programs and Features, and uninstall Intel's driver. It will be called something along the lines of "Intel Matrix Storage Manager". Then reboot the computer and let Windows install its own driver.