Day 142

This has been our first endurance test of an SSD. At the beginning of this diary we've been trying estimate how long it will take until the drive is going to die. It turns out that calculating with 5'000 P/E-cycles was a reasonable thing to, since in the end the drive achieved 5'129 P/E-cycles. We were guessing the drive would withstand our torture testing of continuous writing for 125 days and that turned out to be close to the actual value too, whereas the final result was 142 days.

If we start to do the maths, based on the values we gathered we're going to see some rather surprising endurance values. OCZ specifies this drive to be capable of enduring 20 Gigabyte written per day over a time period of five years. This is what the manufacturer of this drive guarantees. As you can see from the table below, based on our results, when writing 20 Gigabyte per day, you could use this drive for 121 years. This is over 24 times more than actually advertised and it gives you a feeling on how conservative manufacturers are when it comes to endurance ratings of their SSDs. Even if you were writing 50 Gigabyte per day the drive would still last 48 years and at 100 Gigabyte per day this Vector 256 GB would run for 24 years.

Lately another endurance rating used by manufacturers started to appear. Now the vendors are talking about drive writes per day. Some enterprise grade SSDs for example are capable of delivering ten drive writes per day over five years. Pair this up with a drive capacity of 1 Terabyte and you will get some seriously high numbers. Calculating drive writes per day (DPWD) for the Vector 256 GB we've been testing here, when factoring in a period of five years, we end up with a value of 1.89. In the end this means you could be writing the capacity of the drive over 1.8 times per day for five years.

Since the Vector 256 GB is a consumer drive and consumers will be the ones buying and using such a drive, a suitable use case should be applied. In case of an average user it's highly likely that no more than 20 Gigabyte will be written on the drive per day, which is over 24 times less then what the Vector 256 GB could actually do.

Data written per day	Host Writes	NAND Writes	WAF	Cycles	Endurance
10 GB	884 TB	1'313 TB	1.48	5'129	242 years
20 GB	884 TB	1'313 TB	1.48	5'129	121 years
50 GB	884 TB	1'313 TB	1.48	5'129	48 years
100 GB	884 TB	1'313 TB	1.48	5'129	24 years

Page - 1 - Introduction	Page - 5 - Day 7
Page - 2 - Test procedure and test environment	Page - 6 - Day 22
Page - 3 - Day 1	Page - 7 - Day 39
Page - 4 - Day 2	Page - 8 - Day 142