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Samsung SSD 840 EVO 250GB & 1TB TLC NAND Drives Tested
MojoKid writes "Samsung has been aggressively bolstering its solid state drive line-up for the last couple of years. While some of Samsung's earlier drives may not have particularly stood-out versus the competition at the time, the company's more recent 830 series and 840 series of solid state drives have been solid, both in terms of value and overall performance. Samsung's latest consumer-class solid state drives is the just-announced 840 EVO series of products. As the name suggests, the SSD 840 EVO series of drives is an evolution of the Samsung 840 series. These drives use the latest TLC NAND Flash to come out of Samsung's fab, along with an updated controller, and also feature some interesting software called RAPID (Real-time Accelerated Processing of IO Data) that can significantly impact performance. Samsung's new SSD 840 EVO series SSDs performed well throughout a battery of benchmarks, whether using synthetic benchmarks, trace-based tests, or highly-compressible or incompressible data. At around $.76 to $.65 per GB, they're competitively priced, relatively speaking, as well."
Yes, many sites have done the maths on such things. The conclusion "finite life" is not the same thing as "short life". SSDs will in general, outlast HDDs, and will in general die of controller failure (something which affects HDDs too), not flash lifespan.
The numbers for the 840 (which uses the same flash, with the same life span) showed that for the 120GB drive, writing 10GB per day, you would take nearly 12 years to cause the flash to fail. For the 240/480/960 options for the new version you're looking at roughly 23, 47 and 94 years respectively. Given that the average HDD dies after only 4 years (yes yes yes, we all know you have a 20 year old disk that still works, that's a nice anecdote), that's rather bloody good.
How many effective READ/WRITE cycle can the chip in SSD perform, before they start degrading ?
They don't start degrading, per se. Performance-degradation is all due to wear-levelling and the amount of free blocks on the drive, and that varies between manufacturers. Generally the advice is to have atleast 20% of the drive free at all times for wear-levelling and TRIM to work efficiently and in such a situation there should be no performance-degradation.
As for reading and writing cells? Well, you can read a cell indefinitely. You cannot write to cells forever, however, and once the limit comes there is 100% degradation -- so to speak -- as in that that cell cannot be written to ever again. It just goes from 100% to 0%, so using the term "degradation" for that still seems useless. I'll repeat, though, that it can still be read from even if it can't be written to.
Has there been any comparison made in between the reliability (eg read/write cycles) of old fashion spinning-plate HD versus that of SSD ?
Plenty, but how much those comparisons actually cover and how reliable they are is subject to debate. Generally the consensus is that SSDs are more reliable nowadays as full-on controller-failures are very rare and since the SSDs can still be read from even if they hit the maximum amount of writes that means your data is quite a lot safer in the long run -- if a regular, mechanical drive can't write to some sector it most likely can't read it either, and that means your data is as good as gone.
Intel provide a handy utility that tells you how much data has been written to your drive and mine reached the limit in about 18 months so had to be replaced under warranty.
You were (amplified?) writing 32.8 GB per day, on average.
Clearly you will run into SSD erase-limit problems at such a rate, but such workloads normally turn out to not be tasks that actually benefit from an SSD to begin with (32.8GB/day = 380KB/sec, so the devices speed wasnt actually an issue for you)
You were either very clever and knew you would hit the limit and get a free replacement, or very foolish and squandered the lifetime of an expensive device when a cheap deice would have worked.
In any event, in general the larger the SSD the longer its erase-cycle lifetime will be. For a particular flash process its a completely linear 1:1 relationship, where twice the size buys twice as many block erases (a 320GB SSD on the same process would have lasted twice as long as your 160GB SSD with that work load)
"His name was James Damore."