House of Cards – testing the BiWin CFast 2.0 cards on the Ursa Mini 4.6K

Just got two BiWin 128GB CFast 2.0 cards. Since they are not on Blackmagic’s official list of recommended cards (yet), a lot of folks don’t consider them safe for prime time. But I saw some good reviews, and also a lot of guys in the forums use them with success on their Ursas, so I thought I give them a try, and post my findings.


Who the hell is BiWin? – you might ask, since it is not exactly a household name, when it comes to flash memory cards, like Sandisk or Lexar.

BiWin’s original target market was OEM, providing components to companies who would incorporate them into their own products and sell them to consumers. Now, BiWin’s SSD and flash memory based products are offered directly to the consumer through the

They develop flash storage products completely in-house, solution designing, wafer packaging, integrated circuit (IC) testing, surface-mount technology (SMT) assembly, and product testing. Doing everything in-house enables them to react pretty quickly on user feedback. Which brings me to the customer service, which aims to be – nothing less than –  the best around. From my experience, they almost instantly answer emails, but also hang out with us in the usual forums, and answer all out nagging questions. Having reps of companies, join the open discussion in the same forums, that I read on a daily basis, is something I would love to see more often.

So how about the cards?

They look rather unspectacular, more or less a blank card, with a specs sticker on it. But I don’t want to win a design price with it, so who cares?


Since the price tag is rather low, compared to other CFast 2.0 cards of the same capacity, that was raising some eyebrows – you know the typical lines like “you get what you pay for”, “probably not ready for prime time”, “I wouldn’t trust  el-cheapo-Chinese cards for anything other than private stuff (as if other cards would not be made in China – sic), “what if they drop frames in the middle of an important shot”, etc.

So I gave them a test ride on my Ursa Mini 4.6K

First of all. formatting.

I saw some reports on off-brand cards, that would take forever to format (like in several minutes), so I was curious.  The BiWin took about the same time to format to exFat as my Lexar cards (latest Ursa public beta firmware) – so check!


Next – the most important part – recording

I recorded, till the card was full, to see if it would drop any frames. To make sure, this is a real world test, I aimed the camera to my tablet and had a video clip playing on it. IMHO this is more real worldish than aiming the camera to a resolution chart, or a brick wall, since the motion generates different data. After testing them for hours, they got warm to the touch, but nothing to write home about.

ProRes XQ  

  • 24 fps XQ at 4.6K full – dropped frames after a minute
  • 24,25,30 fps XQ at 4.6K 2.4:1 – check
  • 24,25,30 fps XQ at 4K16:9 – check
  • 24,25,30 fps XQ at UHD – check  / 40 fps – dropping frames
  • 24,25,30 fps XQ at 3K anamorphic – check  / 40 fps – dropping frames
  • 24,25,30,60 fps XQ at 2K 16:9 – check


ProRes 444

  • 24, 25, 30 fps 444 at 4.6K full – check
  • 24,25,30 fps 444 at 4.6K 2.4:1 – check
  • 24,25,30 fps 444 at 4K16:9 – check
  • 24,25,30,40 fps 444 at UHD – check
  • 24,25,30,40 fps 444 at 3K anamorphic – check
  • 24,25,30,60 fps 444 at 2K 16:9 – check
  • 24,25,30,60 fps 444 at HD 16:9 – check

RAW lossless

  • 24, 25fps lossles at 4.6K full – check / 40 fps and more – nope
  • 24,25,30 fps lossless at 4.6K 2.4:1 – check / 40 fps and more – nope
  • 24,25,30 fps losslss at 4K16:9 – check / 40 fps and more – nope
  • 24,25,30,40 fps lossless at UHD – check  / 60 fps and more – nope
  • 24,25,30,40 fps lossless at 3K anamorphic – check / 60 fps and more – nope
  • 24,25,30,60,120 fps lossless at 2K 16:9 – check
  • 24,25,30,60,120 fps lossless at HD 16:9 – check

RAW 3:1

  • 24, 25, 30,40 fps 3:1 at 4.6K full – check / 60 fps – nope
  • 24,25,30,40,60 fps 3:1 at 4.6K 2.4:1 – check
  • 24,25,30,40,60 fps 3:1 at 4K16:9 – check
  • 24,25,30,40,60 fps 3:1 at UHD – check
  • 24,25,30,40,60 fps 3:1 at 3K anamorphic – check
  • 24,25,30,60,120 fps 3:1 at 2K 16:9 – check
  • 24,25,30,60,120 fps 3:1 at HD 16:9 – check

All lesser framerates, resolutions and compression also work just fine of course


Dual Card Mode

RAW uncompressed up to 60 fps in full 4.6K!

Not too shabby for some “el-cheapo Chinese cards”, I say.




Would I recommend those BiWin cards?

Absolutely. The price is great, the customer service is ace, and so is the performance.

Would I use them on a real/paid gig?

Having tested them for several hours, with all sorts of resolutions, frame rates and compression – yes I totally would -within the limitations of the test results of course.If you absolutely need 60 fps @ full 4.6K uncompressed for a project, you need a faster card – common sense though. Actually BiWin are currently developing faster 256GB cards and new 512GB cards which are forecast for Q1 2017.

I recommend to order your cards at If you have any questions, or want a discount deal, when buying more cards, drop Lee Miller a line. He is beyond helpful and responds really fast. Lee is also on the BMCuser forum and on the oficcial BM forum.




3 thoughts on “House of Cards – testing the BiWin CFast 2.0 cards on the Ursa Mini 4.6K

  1. thank you Frank.

    some of the cfast 2 cards are the same physical dimension as the cfast 1 cards around 3mm thick. how thick are these cards. my initial use of these would be the the atomos ninja star. it is cfast 2 compatable but you need the thinner cfast 2 card, so it is only electricly compatable not physically compatable to the full cfast 2 spec.


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