Tesla requires a drive with sustained write speeds of 4 MB/s according to the manual (p70):
https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf
There's a couple reasons for that (if you let the drive get nearly full it slows down- this is true of ALL flash media, not just keys), and some crapier keys might overstate specs.
That said- basic math tells us the
actual write speed is 2, not 4, based on writing 4 30mb clips per minute to the drive.
Either number is significantly slower than any good USB drive though.
The Samsung one Tesla explicitly suggests, and includes in all new cars for example,
You can pop this speedy little flash drive in your laptop and forget about it.
www.windowscentral.com
The
slowest it ever writes, and that's for random writes, is over 20.
Sequential writes (which is what recording video would be) is over 60.
The drives that fail likely are falling below that (showing "UI_a080 Some clips not saved - USB too slow for Dashcam. Use USB Drive that writes at 4 MB/s or higher"). Example for reference:
MASTER THREAD: USB drives that work with Sentry and TeslaCam
That's a guy having an issue with the same drive Tesla is now including in hundreds of thousands of new cars (and I've used myself for 3 years)
Obviously it works 99.99% of the time otherwise they wouldn't be including it.
As I mention
every type of drive has gotten that error in some cases-
including SSDs
Oh,...look.
Dude with a 500GB SSD getting
the same error
The highest average sample I have is around 5.3 Mb/s per feed or 21 Mb/s total for the 4 cameras, or about 2.65 MB/s. The peak rate (they are variable bit rate) from reviewing the stats in MPC shows around 5.7 Mb/s or 23 Mb/s or about 2.85 MB/s.
I think you are confusing two different numbers.
I haven't looked recently, but last time I did, all video clips were the same size.
So it'd take the same amount of time to write each one.
The video bitrate varies based on the compression, which has nothing to do with the media write speed, it's handled by the encoder (and then decoder on the other end).
So it's still ~2MB/s since you're writing 4 30 meg clips every minute.
Though again even 5.7 is many times lower than good keys can do sustained from benchmarking. Not peak- average.
As I mentioned, the Samsung T5 drives are only rated for 150-300 cycles (150TBW for 500G/1TB version) and I doubt their USB keys are using more advanced memory than that. That gives you about 20-40 TBW rating for a 128GB key, or only about 3-6 months of continuous writing at 2.65 MB/s. The rating usually is a bit conservative (for warranty purpose), so it'll likely last a bit longer than that. If Sentry mode is on, and it's doing continuous loop recording, it starting to show speed drops (from degraded memory) in about a year is not unusual to me.
So again it's writing 2 MB/s (4 30MB clips)...so 7.2 GB per hour.
AFAIK that's TLC flash on the drive- so ~1000 write cycles.
Discovery by ROM manufacturer Macronix could defeat flash's greatest weakness.
arstechnica.com
(provides an interesting way to get WAY more life out of flash, but mainly linked because it cites the 1000 cycles expected out of the flash)
128GB/7.2GB= 17.77
That's how many hours use 1 cycle.
Times 1000 gets you 17,777 hours.
Originally I was assuming 9 hours a day of use (8 hours parked at work, 30 minute drive each way) as an average... maybe a bit more for running errands, but less on weekends since no work, so 9/day seemed a solid average.
17,777 hours/9 hours a day= 1975.3 days. Which is 5.411 years lifespan.
A 256GB key would be 10.823 years.
24/7 recording obviously eats this faster- so the 256GB probably makes sense and still gets you over 4 years of use.
At least for the Tesla dashcam usage, I have yet to see a report of a High Endurance card failing (although I have seen readers failing), but have seen reports of the recommended 128GB Samsung drives failing.
Did you look?
I have a Model Y that I picked up in July and WOW do I love it! I have had a little bit of problem getting the SD Card sorted out. I purchased a 128GB SanDisk Extreme micro SDXC UHS-I Memory card on Amazon and formatted it to FAT using my macbook. It works when I plug it in with my USB-A...
teslamotorsclub.com
Very first search hit- "too slow" error with an endurance SDcard
www.samsung.com
