Recurrent pending sectors count - WDC WD5000AADS-67S9B1

Hello everybody, last november i bought a WD caviar geen 500GB internal HDD after my last drive started going crazy and continuously resetting for no apparent reason.

Now i’ve got some recurring issues too wit the new one, please bear with me:

1) The pending sectors count keeps going up to two from time to time for no apparent reason, then after some time it goes back to zero again (still no reallocation occurred). What could be causing this?

2) Even this brand new drive will start continuously resetting itself from time to time, freezing the whole system up. Almost always this leads to a hard reset and even after that the disk won’t start up! I have to unplug the power cord, wait a few moments and turn the PC on again. And even after this i have to reset the PC a few more times. This nice feature lead to some data getting lost not too long ago (i.e. my whole windows partition). I am starting to think *it might be* a SATA controller issue (like i said, this same thing started happening more and more often to my last HDD). My motherboard is an Asus m4n78 pro. The manual says it has an Nvidia 8300 controller, lshw instead says 8200:
SATA controller: MCP78S [GeForce 8200] AHCI Controller, vendor: NVIDIA corporation, width: 32 bits, clock: 66MHz, capabilities: storage pm msi ht ahci_1.0 bus_master cap_list emulated, configuration: driver=ahci latency=0, maxlatency=1 mingnt=3.

3) Do you think my load cycle is too high? Do i need to fix it like i read on many websites around?

S.M.A.R.T. ATTRIBUTES:

smartctl 5.41 2011-06-09 r3365 [i686-linux-3.2.0-24-generic-pae] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF INFORMATION SECTION ===
Model Family: Western Digital Caviar Green
Device Model: WDC WD5000AADS-67S9B1
Serial Number: WD-WCAV9S688910
LU WWN Device Id: 5 0014ee 159a6ba99
Firmware Version: 01.00A01
User Capacity: 500,107,862,016 bytes [500 GB]
Sector Size: 512 bytes logical/physical
Device is: In smartctl database [for details use: -P show]
ATA Version is: 8
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Thu May 3 16:52:45 2012 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status: (0x00)	Offline data collection activity
					was never started.
					Auto Offline Data Collection: Disabled.
Self-test execution status: ( 121)	The previous self-test completed having
					the read element of the test failed.
Total time to complete Offline 
data collection: (11400) seconds.
Offline data collection
capabilities: (0x7b) SMART execute Offline immediate.
					Auto Offline data collection on/off support.
					Suspend Offline collection upon new
					command.
					Offline surface scan supported.
					Self-test supported.
					Conveyance Self-test supported.
					Selective Self-test supported.
SMART capabilities: (0x0003)	Saves SMART data before entering
					power-saving mode.
					Supports SMART auto save timer.
Error logging capability: (0x01)	Error logging supported.
					General Purpose Logging supported.
Short self-test routine 
recommended polling time: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 133) minutes.
Conveyance self-test routine
recommended polling time: ( 5) minutes.
SCT capabilities: (0x3037)	SCT Status supported.
					SCT Feature Control supported.
					SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 525
  3 Spin_Up_Time 0x0027 188 185 021 Pre-fail Always - 3558
  4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 430
  5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0
  7 Seek_Error_Rate 0x002e 100 253 000 Old_age Always - 0
  9 Power_On_Hours 0x0032 098 098 000 Old_age Always - 1624
 10 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 0
 11 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 0
 12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 427
192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 170
193 Load_Cycle_Count 0x0032 200 200 000 Old_age Always - 259
194 Temperature_Celsius 0x0022 109 105 000 Old_age Always - 34
196 Reallocated_Event_Count 0x0032 200 200 000 Old_age Always - 0
197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 2
198 Offline_Uncorrectable 0x0030 100 253 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0008 100 253 000 Old_age Offline - 0

SMART Error Log Version: 1
No Errors Logged

SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed: read failure 90% 1624 19762296
# 2 Short offline Completed without error 00% 1502 -
# 3 Short offline Completed: read failure 90% 1120 591676508
# 4 Short offline Completed: read failure 90% 1051 591676508
# 5 Extended offline Completed without error 00% 1006 -
# 6 Extended offline Completed: read failure 90% 995 5835562
# 7 Short offline Completed: read failure 90% 994 5835562
# 8 Short offline Completed without error 00% 3 -
2 of 5 failed self-tests are outdated by newer successful extended offline self-test # 5

SMART Selective self-test log data structure revision number 1
 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
    1 0 0 Not_testing
    2 0 0 Not_testing
    3 0 0 Not_testing
    4 0 0 Not_testing
    5 0 0 Not_testing
Selective self-test flags (0x0):
  After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

Since you are having similar issues with this drive as with the original, there is a chance that are related to your motherboard or SATA controller.  You can try replacing cables, trying other SATA port, and if possible other computer.  you can also test the drive for errors using DLG:  How to test a drive for problems using Data Lifeguard Diagnostics for Windows