SD Card write speeds very slow when full

[Senzelian]

I bought a 64GB Samsung Pro Endurance Micro SD card for my FITCAMX dashcam. Samsung specifically recommends this model for dashcams, but I noticed that it wouldn't record any videos sometimes.

The dashcam support said I should do a benchmark, but didn't specify any reason for it (I'm still in contact with them).

 

Benchmark results when the SD card was full:

Write: 4 MB/s

Read: 80 MB/s

 

After a quick format, it's still the same, but I suspect that after I formatted the card properly it will function as new. (It's still in the process of doing so)

 

I'm no noob when it comes to flash storage and so I'm not surprised that the SD card slowed down, but I didn't expect for it to slow down this much!

FITCAMX ships an SD card with their dashcam, which supposedly works fine, but I specifically bought a Samsung SD card because I didn't trust the one it came with. Now I'm wondering if this could be resolved with another SD card from a different manufacturer or with a different Samsung model. Has anyone experience with full SD cards and constant sequential write cycles?

 

The SD card is formatted in exFAT and I have tested it with my Razer Blade's SD card slot in the original adapter and with a USB 2.0 micro SD card adapter. Both show the same results.

[AAVVIronAlex]

Hmm, the reason you could be seeing slow speeds is if you have satisfied a great part of the maximum amount of writes available on that SD Card. Though, now that I think of it my SanDisk 512GB SD card is slow too, I mean how much can you really expect from those tiny things. The reads do seem good, though.

[Levent]

Yeah I would assume you just wore it down. Dash cams are notorious for it.

[Senzelian]

28 minutes ago, AAVVIronAlex said:

the reason you could be seeing slow speeds is if you have satisfied a great part of the maximum amount of writes available on that SD Card

 

11 minutes ago, Levent said:

Yeah I would assume you just wore it down. Dash cams are notorious for it.

Interestingly enough Samsung claims a TBW of 140k hours, which equates to 16 years. That's the reason I bought it  

But I've done some more digging and found that the SD card is only rated for 30MB/s writes. What I will do now is keep formatting it, test it, and also buy a new SanDisk Extreme Pro 128GB, which is rated for 90MB/s, and see how that one does.

 

I want to get to the bottom of this. It's nuts to me that an SD card fails after only a few months of usage when it was specifically designed to last many years and installed in a dashcam. I'll keep this post updated if you guys care...

[Levent]

8 minutes ago, Senzelian said:

 

Interestingly enough Samsung claims a TBW of 140k hours, which equates to 16 years. That's the reason I bought it  

But I've done some more digging and found that the SD card is only rated for 30MB/s writes. What I will do now is keep formatting it, test it, and also buy a new SanDisk Extreme Pro 128GB, which is rated for 90MB/s, and see how that one does.

 

I want to get to the bottom of this. It's nuts to me that an SD card fails after only a few months of usage when it was specifically designed to last many years and installed in a dashcam. I'll keep this post updated if you guys care...

Issue is that most dashcams (at least when I was in the market for one) don’t support TRIM hence why they wear down cards in a weird way. Keep me updated by the way

[AAVVIronAlex]

12 minutes ago, Senzelian said:

 

Interestingly enough Samsung claims a TBW of 140k hours, which equates to 16 years. That's the reason I bought it  

But I've done some more digging and found that the SD card is only rated for 30MB/s writes. What I will do now is keep formatting it, test it, and also buy a new SanDisk Extreme Pro 128GB, which is rated for 90MB/s, and see how that one does.

 

I want to get to the bottom of this. It's nuts to me that an SD card fails after only a few months of usage when it was specifically designed to last many years and installed in a dashcam. I'll keep this post updated if you guys care...

Keep me updated too.

[Senzelian]

2 hours ago, Levent said:

Issue is that most dashcams (at least when I was in the market for one) don’t support TRIM hence why they wear down cards in a weird way. Keep me updated by the way

 

2 hours ago, AAVVIronAlex said:

Keep me updated too.

The full format of the SD card is done and it's now back to its full write speeds of 32 MB/s. 

 

So to recap:

SD card full: 4 MB/s

SD card quick format: 4 MB/s
SD card full format: 32 MB/s

 

I think the entire problem here could actually be TRIM, as the data needs to be deleted when the SD card gets written to and not before that. This might be why dashcams don't support TRIM. But if that's the case, it wouldn't explain the performance issues that I am having according to FITCAMX's support. However, it would explain why my benchmark was showing such low numbers.

 

So my suspicion is, that either my SD card has problems in general with recording 4K, or my dashcam does actually support TRIM or a similar instruction and therefore is causing issues as it degrades the write performance. I guess I will find out when I test the SanDisk SD card and see if its causing issues too.

 

Edit:
FITCAMX came back to me and told me to get the card that I just ordered. So we'll see how things go...

[kokosnh]

I would try to decrease partition size, of the few last GB, so it have some OP space. Try it and see how it goes, won't solve the problem, but should slow it down enough (old way of maintaining write speed, on older SSDs)

[Senzelian]

3 minutes ago, kokosnh said:

I would try to decrease partition size, of the few last GB, so it have some OP space. Try it and see how it goes, won't solve the problem, but should slow it down enough (old way of maintaining write speed, on older SSDs)

That's a great idea! Why did I not think of this?  

I will definitely try that during my upcoming tests. Thank you!