Best Hard Drives for 24 camera 8MP System

Hi Everyone.

I’m currently building a new CCTV system for our business site - but have a question about the best hard drives to use. For the CCTV we’ll be using 24 x 8MP cameras so data rates will be very high.

WD Purple HDDs have a workload rate of up to 180TB/year so I went on an online storage calculator with the settings as below to see how much data we’d actually write to the drives over a year:


This gives a total annual amount being written to the drives annually as 1513TB .
(It would be a lower in real world use as I guess the cameras wouldn’t use the full 16k bit rate when there is little motion in the scene).

The WD Purple drives only have a workload rate of up to 180TB per year. So 4 drives would give us annual written data of 720TB/Year (4 x 180TB each). That would mean we would go through a year’s workload in only 5 months. I assume this would void the warranty?

Alternatively Western Digital list on their website on the Surveillance Storage page the Gold Enterprise Class Hard Drive. These drives are rated at 550TB workload per year so just 3 of them would be within the tolerance of the up to 1513TB recorder per year.

There are other advantages as well to the Gold drives as below:

Purple vs Gold

Workrate: Purple - 180TB/yr // Gold - 550TB/yr
RPM Class: Purple - 5400 // Gold - 7200
Cache: Purple - 64MB // Gold - 128MB
Warranty: Purple - 3 Year // Gold - 5 Year
AllFrame 4K Tech: Purple - Yes // Gold - Not Specified

It seems like the Gold drives are the better option especially given the 5 year warranty. However, although WD list the Gold Drive on their surveillance page, they make no mention of this “AllFrame 4K™ technology for system playback and performance” that is included on the Purple drives.

This tech is described as:

“AllFrame 4K technology enhances ATA streaming support to help reduce video frame loss with proprietary cache policy management technology to improve overall data flow and playback. WD Purple 10TB HDDs include exclusive firmware enhancements that help protect against video pixilation and interruptions within a surveillance system.”

Now I don’t know if Allframe 4K Tech is irrelevant for the Gold drives being 7200rpm vs 5400rpm for the Purple and a larger cache but I can’t find out from anywhere - there doesn’t seem to be a way to ask WD directly. The purple drives are designed specifically for NVRs but Gold are a much higher spec and so may be superior still than the Purple ones for NVR use.

If Gold performs as well as or better than Purple then for the small price difference it seems Gold is the better option.

Anyone any view on what this 4K tech is/does and whether the Gold drives either include it or don’t need it?

Any help and guidance would be much appreciated.


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