WD Green vs WD Red – Choosing the right hard drive for my HTPC

I have recently been upgrading my HTPC with new storage. My current brand of choice when it comes to hard drives is Western Digital. Good quality and service, simple as that.

Anyway, in the beginning I found it quite difficult to find the real differences between the WD Green and WD Red 4TB drives. I know you can get a lot of marketing gimmick from the WD site, but if you want to know what it means when their site says the following about the WD Green drives: “*Desktop drives are not recommended for use in RAID environments, please consider using WD Red hard drives for home and small office 1-5 bay NAS systems and WD Enterprise hard drives for rackmount and >5 bay NAS systems.” – you have to look somewhere else. In this post I bring my findings on the main differences between those drives.

Warranty

It speaks for itself – 3 yrs is better than 2.

IntelliPark

IntelliPark is this feature where the disk head is parked after a period of inactivity. This is done in order to reduce the aerodynamic drag it causes and thus saves power. While that sounds good, it has a negative impact on the Load Cycle Count (a S.M.A.R.T. parameter) – simply because each time it loads after being parked, it increments this counter. So, is this bad, or? Well, it depends. Some forum posts reports that on some Linux systems the file systems flushes data to the disk every 10th second, and with a default IntelliPark threshold of 8 seconds, the Load Cycle Count can quickly increase (think about it: 24 hrs/day * 60 min/hr * 60 sec/hr = 86400 sec/day – divide that by 10 and you have the number of Load Cycle Counts per day for such systems (8640) – and given an estimated limit of around 300.000 Load Cycles for a drive in its lifetime, this makes the drive live for 300.000/8640 = ~35 days (a bit more than a month). I have not read about people reporting this being an issue – however, I think it is worth taking into account.

In this regard, I think it should be mentioned that people have reported that the feature should be possible to disable using Western Digitals own WDIDLE3 tool.

RPM

Same for both drives: IntelliPower. It turns out that this is just a marketing thing for saying that WD is not going to tell you the exact RPM and that WD has the right to differentiate the RPM on the drives with IntelliPower. Anyway, blog- and forum posts quickly reveals that these disks spins with 5400 RPM (saves power and makes less noise).

Noise

According to the specs – the disks are almost identical here. In my experience, after having compared a 2 TB WD Green with a 4 TB WD Red I can confirm that the noise level is almost the same (they are both quiet and fine for a silent HTPC 🙂 ).

TLER configurable

TLER is short for Time Limited Error-correction Recovery. Why is this important you ask? Well, imagine you have 4 disks without TLER in a RAID array. You then start writing a file to the array and suddenly one of the disks hits a bad sector. This makes the disk try to recover from the error and since this takes time, you are risking the disk is not responding the RAID controller within a period of time causing the RAID controller to drop it from the array and mark it as disconnected. With TLER you set an upper limit on the time the disk is allowed to use at error correction. In this way, you are guaranteed the disk will respond within the defined threshold ensuring the RAID controller is always given a response (in this way the RAID controller will be given the message that the disk encountered an error writing to a specific sector, and the RAID controller will then deal with it – and everything continues to work.)

Price

Well, really not much difference there. WD Green is slightly cheaper than the WD Red drive.

Conclusion

I bought the WD Red 4 TB drive because I think you get the same benefits of the WD Green drive (low noise, low price) while also getting a disk that is suited for RAID and where the IntelliPark issue/discussion is of no concern. And last but not least, you get 1 more year of warranty when buying the WD Red.

So, I went and bought the WD Red drive and after having mounted it I am really happy with it. It just works out of the box and is very silent.

References:

• http://forums.anandtech.com/showpost.php?p=34711020&postcount=23
• http://www.wdc.com/en/company/glossaryofterms/wdglossarycontent.asp
• http://www.anandtech.com/show/6157/western-digital-red-review-are-nasoptimized-hdds-worth-the-premium/2
• http://www.silentpcreview.com/article786-page2.html
• http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771442.pdf
• http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771438.pdf
• http://en.wikipedia.org/wiki/Error_recovery_control
• http://www.pcper.com/reviews/Storage/Western-Digital-Red-3TB-SATA-SOHO-NAS-Drive-Full-Review
• http://forums.anandtech.com/showthread.php?t=2085685
• http://www.storagereview.com/how_to_stop_excessive_load_cycles_on_the_western_digital_2tb_caviar_green_wd20ears_with_wdidle3