SanDisk Ultra 64 GB microSDXC Class 10 UHS-1 Memory Card 30MB/s with Adapter SDSDQUA-064G-U46A

[Note on Feb 4, 2013]
1. Amazon combined the Sandisk Ultra 32GB and 64GB cards on the same product page. Please beware that your intended appliance must be compatible with ‘SDXC’ in order to used the 64GB version. My original review below refers to the 32GB ‘SDHC’ version.

2. There are two part numbers for the same card. If you start from the Amazon product page and select ‘Retail Packaging’, you’ll see the part number of SDSDQUA-032G-U46A. But if you click on ‘Frustration Free Package’, the part number changes to SDSDQU-032G-AFFP-A.
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I have tested dozens of SDHC and micro-SDHC cards. One disturbing trend I noticed is that: the speed class rating for micro-SDHC is typically inflated. For example, a ‘class-10′ rating means the card must deliver a sequential write speed of at least 10MB/s. But somehow, a class-10 microSDHC cards is always slower than a class-10 SDHC card from the same manufacturer. Case in point: the PNY 32 GB microSDHC Card (P-SDU32G10-EFS2) claims to be ‘class-10′, yet it can only write at 8.6MB/s maximum, while the full-size PNY P-SDHC16G10 achieved 13.4MB/s according to CrystalDiskMark v3.01.

This SanDisk Ultra 32 GB microSDHC Class 10 card (SDSDQUA-032G-U46A), however, proves to be the exception. It achieved a sequential write speed of over 10MB/s according to two different benchmark programs (11.8MB/s in “CrystalDiskMark”, 10.6MB/s in “H2testw v1.4″). This is faster than all my other microSDHC cards, including two ‘class-10′ cards from PNY and Polaroid.

A closer look at the file transfer speed using “Flash Memory Toolkit” revealed another nice surprise: For writing small files, this Sandisk Ultra microSDHC card performed just as well as its full-size counterpart, the SanDisk Ultra SDHC (SDSDU-032G-AFFP). In contrast, all my other class-10 microSDHC cards perform poorly while writing smaller files. See the benchmark results I uploaded to ‘Customer Images’ for details.

When you use a memory card in a digital camera to record HD video, it needs to store a huge video file each session. That means its sequential write speed is most critical. When used in a tablet or a smart phone, however, the card’s random write speed for small files is more important. That’s why in such applications, the Sandisk microSDHC will perform faster than the PNY and Polaroid cards, even though they are also rated as ‘class-10′.

[Bottom Line]
As of this writing, the Sandisk Ultra microSDHC card ia actually priced lower than other class-10 cards from PNY and Polaroid. This makes the Sandisk the best value – especially if you need honest class-10 performance across all platforms.

[Side Notes]
- Do not confuse this Sandisk Ultra card with SanDisk Mobile Ultra microSDHC (SDSDQY-032G-U46A). The latter is rated for class-6 only.
- The size of this ’32GB’ card is 29.7GB according to my computer. This is actually normal because computer people count one Gig as “2 to the power 30″, which is 7.3% larger than one billion. So 29.7GB translates to 31.9 billion bytes, which is ’32GB’ according to marketing people.

Works great with my Galaxy S3. Didn’t need to format the card or anything. Just popped the card in and everything worked great out of the box. Transfer speeds are excellent with this card. I would recommend this card to everyone.

I haven’t had to buy a microSD card in a long time. The last time I bought one was for my cell phone over 2 years ago. But since my cellular contract was up, I knew I would have to get a newer card in addition to my new phone, the Samsung Galaxy S4. Reason for this is because I knew my small 16GB microSD card wasn’t going to cut it.

Doing research on the Galaxy S4, I wanted to get the best card possible that had decent capacity (32 GB or greater). This led me to find that the Galaxy S4 supports the microSDXC Class 10 UHS-I card, which is the fastest possible given that class. Searching for that specifically on Amazon gave me results of only 3 vendors (as of April) that makes these microSDXC Class 10 UHS-1 cards. They are Sandisk (the majority), Samsung and Lexar. Nobody else makes these that are sold on Amazon.

Seeing how SanDisk is a pretty good name out of the 3 (I’ve used them the most), I decided upon the SanDisk because Lexar was overpriced and the Samsung one was overpriced (as well as not eligible for Amazon Prime).

But the scary thing is that when you filter by the SanDisk, you literally get DOZENS of options. All of them have different model numbers, different sizes, etc. Then there’s that confusion of what’s the difference between SDHC & SDXC?

SDHC vs SDXC:
SDHC stand for "Secure Digital High Capacity" and SDXC stands for "Secure Digital eXtended Capacity". Essentially these two cards are the same with the exception that SDHC only supports capcities up to 32GB and is formated with the FAT32 file system. The SDXC cards are formatted with the exFAT file system. If you use an SDXC card in a device, it must support that file system, otherwise it may not be recognizable and/or you have to reformat the card to FAT32.

FAT32 vs exFAT:
The differences between the two file systems means that FAT32 has a maximum file size of 4GB, limited by that file system. exFAT on the otherhand, supports file sizes up to 2TB (terabytes). The only thing you need to know here really is that it’s possible your device doesn’t support exFAT. If that’s the case, just reformat it to FAT32. REMEMBER FORMATTING ERASES ALL DATA!

To clarify the model numbers, I I hopped over to the SanDisk official webpage. What I found there is that they offer two "highspeed" options for SanDisk cards. These are SanDisk Extreme Pro and SanDisk Ultra. SanDisk Extreme Pro is a line that supports read speeds up to 95MB/sec, however they are SDHC only. To make things worse, they are currently only available in 16GB & 8GB capacities. Since one of my requirements was to have a lot of storage, I ruled these out.

The remaining devices listed on Amazon’s search were the SanDisk Ultra line. But here, confusion sets in because SanDisk separates these cards to two different devices. Cameras & mobile devices. Is there a real difference between the two or is this just a marketing stunt? Unfortunately I’m not sure but I do know the price difference between the two range from a couple cents to a few dollars. Since I wasn’t sure, I opted for the one specifically targeted for mobile devices (just in case there is some kind of compatibility issue). To find the exact model number, I would go to Sandisk’s webpage (sandisk.com) and compare their existing product lineup. From there, you get exact model numbers and you can then search Amazon for these model numbers. That is how I got mine (SDSDQUA-064G).

As for speed tests, I haven’t run any specific testing, but copying 8 GB worth of data from my PC to the card literally took just a few minutes.

One last note is that Amazon attaches additional characters to the end (for example SDSDQUA-064G-AFFP-A vs SDSDQUA-064G-U46A). The difference between the two is that the "AFFP-A" means "Amazon Frustration Free Packaging". Other than that, these are exactly the same. If you’re wondering what I got (and want to use it in your Galaxy S4), I got the SDSDQUA-064G-u46A and it works like charm.

Initially when I inserted the card into the Samsung Galaxy S3 it recognized it but it wasn’t able to format it correctly. After doing some research I found a free program EaseUS Partition Master [...] that will format the card into FAT 32 since Windows no longer allows you to do it by default. After formatting it into fat 32 the phone recognized the card and it works great now. I hope this helps anyone else that might run into this problem.

SanDisk Ultra 64 GB microSDXC Class 10 UHS-1 Memory Card 30MB/s with Adapter SDSDQUA-064G-U46A
I bought this for my new Samsung Galaxy S III that I just got this week. I read a bunch of reviews here at Amazon before I bought, and it did seem a little risky judging by some of the reviews, but I decided to go ahead and get it because the price is just so good, plus I had two more days of Amazon Prime, so shipping was free.

Despite the poor reviews here, I personally had no problem whatsoever with it. I didn’t have to do a single thing except to insert the card into it’s slot on my new phone! Of course, I pulled the battery before inserting the card and used appropriate care. As soon as the phone powered up, it “saw” the card, recognized it, formatted it & it showed up as having something like 59.4 Gigs available. I have not done any official testing w/memory test software or anything like that, but I just wanted to share my experience with the product in case anyone else out there is thinking about purchasing it.

The last few days I have been diligently shopping for a MicroSDXC card to utilize in my new smart phone. I have a long term positive experience using SanDisk cards. I quickly became confused about the differences between the so called “Mobile” Ultra cards and the Ultra cards. The performance specs to my “intermediate tech experience” eyes were virtually the same. The prices were also similar, with the “Mobile”version slightly higher. To finally resolve my confusion I contacted SanDisk technical support. To my surprise, the “Mobile” version is the older, no longer manufactured version. The Ultra is the current model. So I immediately bought the current Ultra version, which very fortunately AMAZON had on sale!

Bought this microSD because I just got a Microsoft Surface and unlike many tablets/slates the Surface has expandable storage using microSD. Put this thing in under the kick stand and now have a 96gb Microsoft Surface. Just put in and went.. Simple as that.. Makes the amazing Surface that much better.

Bought this card to use with my Samsung Galaxy Tab2 7in tablet, based on others who have reported getting it to work in their Galaxy Tab 2.

Bottom line, you gotta reformat this card as FAT32 with 32kb sectors to work in the Galaxy Tab 2, and that requires jumping thru some hoops as Win6/Vista does not even offer the choice to format as FAT32, only as NTFS or exFAT, neither of which will work with the Galaxy Tab 2 (Android v4.04) You have to use 3rd party software to accomplish this. A FREE solution is the EaseUS Partition Master free software you can download from cnet or direct from EaseUS. I had a commercial package already installed (Acronis DiskDirector) that I used.

Once fomatted as FAT32 with 32kb sectors, the card is recognized AND all the space is seen and useable.

Highly recommended if you need the space. I would assume that this would also make LARGER microSDXC cards work as well

John