I have recently installed two WD20EARS drives and set them up in win7 pro as mirrored drives (software raid 1).
Yesterday i started transferring some data from an old WD6400AAKS drive to them and the window that pops up when you copy was saying around 90MB/s and i could hear the drives "whizzing" away.
Today, i come to do some more transfering and instead of 90MB/s i get 3.2MB/s and i can't hear the sound of busy drives. I reboot the computer and it's the same.
I then ran seatools short self test, smart check and short generic test and they were all fine. I then try to transfer again and i get 45MB/s.
I left it copying for a while and come back to copy some more and it's now down to 6MB/s.
I tried sending 1GB between the WD6400AAKS and my system drive that is a 1TB WD green and i get 6MB/s. I try sending data from the 1TB WD Green to the mirrored drives and i get 35MB/s.
These new 2TB green drives are quite noisy in that i can hear the parking of the heads. I have a hunch that my problem is to do with power saving because even though i'm transfering 10GB i can still hear the odd drive park.
I'm probably going to use the widdle3 util from WD to adjust the drive parking but i'm not sure that's the real problem.
Use a utility like speedfan to read the SMART values on the drive and see if everything looks normal. Check the device manager to make sure the drives are running in DMA mode and not PIO. You may also want to update your chipset drivers and/or sata/raid drivers.
Any time you use large drives (2TB) it will slow your system down, a whole bunch.
Install the OS and applications ONLY on a small fast drive, set the bios to boot this drive first.
Install personal files on the large drives ONLY. DO NOT install the OS on a large drive.
KEEP the OS and apps separated from your files. Don't store files on the OS drive.
By making OS and apps on a small drive...
and storing your files on a dedicated large drive...
it solves the slowdown problems. 2TB drives are VERY slow, you best believe it.
My favorite is to use a Velociraptor 10,000 RPM, 2-1/2", 70GB for the operating system, dedicated drive (it's cheap and reliable)
and store personal files on a 1 or 2 TB drive. This way, the whole thing boots 100% and runs in less than 30 seconds. No more delays.
What i did was download the "ultimate boot cd" that has wdidle3.exe on it, booted off the cd and disabled the "intellipark" feature of all three green drives and this seems to have fixed the problem. Now when i copy using win7 windowns tells me it's transferring at between 75 and 95MB/s.
I'm guessing that there was some issue with intellipark and the windows mirror (raid 1) but i did test with a transfer between the 1TB that isn't part of the mirror and my old 640GB and had the same issue so maybe it's some other power saving feature of the green power drives.
I have a 1TB WD green for operating system and 2x2TB green drives for data. This is a server on 24/7 which is why i went for the green system drive and 1TB was the smallest i could get at the time - a system drive failed so i needed something quick.
When i had the issue i was doing a straight copy from one drive to another.
I had used speedfan to check smart details and nothing seemed out of place.
Athlon II x2 235e (2.71GHz)
2x1GB G.Skill RAM (not sure exact)
Antec Earthwatts 380W PSU
The RAID is simply windows 7 mirroring. Only available in pro/ultimate version. Very easy to set-up. I chose this over using motherboard raid 1 because i had a "feeling" that it would be more reliable, and transferrable, than using the motherboard. Specifically i thought that with windows mirror even if something happened i can take the drives out and put each seperately into any machine that accepts dynamic volumes and read them. I wasn't too sure about MB raid. Again, this is based purely on a feeling from reading forums etc. Although people often complain about dynamic volumes and also about windows mirror, i think that people often blame something that's new, whereas people with drive issues on basic disks look for something else to be the scape goat. I also contacted the support person for zero assumption recovery (the software i used to recover data on my failed drive) and they said that if you create a single partition on a dynamic drive then the recovery after a failure is essentially the same as for a basic disk.
One thing i didn't mention is that i don't have any service packs/updates applied to my win7 installation. Maybe there will be updates that would have avoided my issue. My system is still in the test phase so didn't want to use up data d/l just yet (broadband is expensive where i live).
I'm still trying to check DMA vs PIO but my options in device manager when i look at the drive details aren't the same as the internet examples i've seen - i don't have an options to switch between the two.