SanDisk's new Guardian Series costs $13 to $20 more than its own High Endurance card for the same hour table, SanDisk does not say what the extra buys, and its warranty policy may not cover Guardian in a dash cam.
SanDisk announced it on Oct. 13: a Dash Cam card and a Security Cam card, each from 32GB to 512GB, "available now from select retailers starting at $28.99 U.S. MSRP for 32GB." On Oct. 14, SanDisk's store showed the 32GB Dash Cam and Security Cam cards and the 64GB Dash Cam card out of stock.
Why it matters
The hour ratings measure endurance, not how much video a card holds, and SanDisk gives no bitrate for them. On SanDisk's store, High Endurance lists the same hours for less at 128GB and 512GB. The warranty policy does not mention Guardian.
Why an ordinary card struggles
A dash cam or home camera records, fills the card, then overwrites the oldest footage, all day and every day. Flash memory wears out with writes, so a card made for photos gets far more writing in a camera than it was designed for.
SanDisk's press release puts it this way: "Conventional storage wasn't built for the demands of continuous recording in harsh environments."
What the hour ratings mean
SanDisk rates the Dash Cam card in hours, per capacity, "based on internal testing":
- 32GB: 2,500 hours (about 104 days of nonstop recording)
- 64GB: 5,000 hours (about 208 days)
- 128GB: 10,000 hours (about 1.1 years)
- 256GB: 20,000 hours (about 2.3 years)
- 512GB: 40,000 hours (about 4.6 years)
The day and year figures are our arithmetic (hours divided by 24, or by 8,760).
This is an endurance rating, not how much footage the card holds. SanDisk's footnote says "Actual hours of video saved less," and "Full HD video only; total hours less for 4K UHD video." SanDisk gives no bitrate for the test.
How the two cards differ
The Dash Cam card is rated in hours, as above, and SanDisk says it is "engineered to withstand heat and humidity on even the longest drives."
The Security Cam card is rated in time, per its product page: up to 4 years at 512GB, 2 years at 256GB, 1 year at 128GB, 6 months at 64GB and 3 months at 32GB. They are internal-testing figures, actual saved time is less, and they cover Full HD only. The press release calls it temperature, water and dust proof.
Both read up to 100MB/s, write up to 40MB/s (internal testing), are V30, and carry a 2-year limited warranty on SanDisk's store. The two rating tables line up, and SanDisk does not say the cards are the same inside.
Where they sit in SanDisk's range
SanDisk already sells two endurance microSD cards and does not say the Guardian cards replace them. Its microSD portfolio page lists only the Guardian cards among dash and security cards.
High Endurance has the same 2,500 to 40,000 hour table and 100/40MB/s speeds as the Dash Cam card, a 2-year warranty, and a page that advertises it as "temperature-proof, waterproof, shockproof and x-ray-proof." On SanDisk's store it costs $36.99 at 128GB, $69.99 at 256GB (out of stock) and $129.99 at 512GB.
Max Endurance is rated up to 120,000 hours at 256GB and 60,000 at 128GB, with no 512GB size. Like the others it is "internal testing," Full HD only, with lower actual saved hours. On SanDisk's store 128GB is $58.99 and 256GB $112.99, both out of stock. Warranty is 5 years at 64GB, 10 at 128GB and 15 at 256GB.
High Endurance already advertises temperature, water, shock and x-ray protection, so the overlap with Guardian is real, and SanDisk's pages do not say what else Guardian adds. For the same hour rating, the Guardian 128GB card at $49.99 is $13 more than High Endurance at $36.99. At 512GB, $149.99 is $20 more than $129.99.
A rival: Samsung PRO Endurance
Samsung's PRO Endurance comes in 32GB to 256GB. Its data sheet rates it "based on Full HD (1920x1080) video content recorded at 26 Mbps": 17,520 hours at 32GB, 35,040 at 64GB, 70,080 at 128GB and 140,160 at 256GB.
Warranties run 2, 3, 5 and 5 years across those sizes. Samsung's US prices on Oct. 14: 128GB $76.99, marked out of stock, and 256GB $153.99.
Samsung states its bitrate and SanDisk does not, so the hour figures are not a like-for-like comparison. Samsung's 128GB rating is seven times SanDisk's Dash Cam 128GB rating, at a higher price and under test conditions that are only stated on one side.
Which size to buy
Loop length, the footage a card holds before overwriting, is capacity divided by bitrate: 1Mbps is 0.45GB per hour. These bitrates are our assumptions, not SanDisk figures. Your camera's settings give the real one, and a rear camera adds a second stream. Figures are rounded, with no allowance for formatting overhead.
- 1080p at an assumed 10Mbps: 4.5GB per hour. 32GB about 7 hours, 64GB about 14, 128GB about 28, 256GB about 57, 512GB about 114.
- 4K at an assumed 30Mbps: 13.5GB per hour. 32GB about 2.4 hours, 64GB about 4.7, 128GB about 9.5, 256GB about 19, 512GB about 38.
- Samsung's test rate, 26Mbps: 11.7GB per hour, so 128GB holds about 11 hours.
For a single 1080p dash cam, 64GB or 128GB gives half a day to a day of loop. For 4K or front plus rear, pick 256GB, since a 128GB card at 4K keeps under ten hours.
A home camera that keeps weeks of motion clips suits the Security Cam card, sized by your camera's bitrate and the days you want kept.
Where to buy
Guardian is not listed on Amazon yet, so these are SanDisk store prices on Oct. 14:
- Dash Cam card: 32GB $22.99 (out of stock), 64GB $29.99 (out of stock), 128GB $49.99, 256GB $79.99, 512GB $149.99.
- Security Cam card: 32GB $22.99 (out of stock), 64GB $29.99, 128GB $49.99, 256GB $79.99, 512GB $149.99.
High Endurance 128GB is on Amazon at $36.99, sold by Amazon.com.
Warranty: read the policy
SanDisk's consumer flash warranty policy says the warranty "does not cover use of the Product in connection with":
- Security: "(ii) video monitoring, security, and surveillance devices"
- Network cameras: "(iii) internet protocol/network cameras"
- Dash cams: "(iv) in-car recording devices/dashboard cameras/black box cameras"
- Exception: these exclusions "do not apply to the following: select Sandisk Endurance products."
The policy does not mention Guardian, so whether the Guardian cards count as those endurance products is unresolved. Ask SanDisk before relying on warranty cover in a dash cam or security camera.
Our call, untested
We did not test the cards. On paper, the Dash Cam card fits a hot car if you want the heat and humidity wording on the box, and the Security Cam card an outdoor camera.
If you only need the hours rating, High Endurance has the same table for less at 128GB and 512GB ($36.99 at 128GB on Amazon), and Samsung states its bitrate. Wait for independent endurance tests before paying extra for Guardian.
Check your camera takes microSD at the size you pick, since SanDisk says 4K support "may vary based on host device."
