SanDisk Ultra microSD 140MBs 64GB

SanDisk Ultra microSDXC UHS-I 64GB – 140MB/s A1 Class 10 Memory Card

SanDisk Ultra microSD 140MBs 64GB targets Android smartphones, tablets, Chromebooks, and Windows laptops that demand dependable sequential read performance alongside practical everyday storage. Under the model number SDSQUAB-064G, this card builds on the 32GB Ultra variant with a higher read speed ceiling of 140MB/s — a 17% increase — while carrying forward the same A1 application performance rating, Class 10 and U1 speed class credentials, and five-point environmental protection that defines the Ultra lineup.

At 64GB, the SDSQUAB-064G holds a practical mid-point in the Ultra range: enough capacity for media-heavy Android users, and enough speed for Full HD video recording without the cost premium of a V30 or A2-rated card.

Read Speed and UHS-I Interface

The SanDisk Ultra 64GB runs on the UHS-I (Ultra High Speed Phase I) bus, which sets a standard ceiling of 104MB/s. SanDisk’s proprietary controller technology drives the SDSQUAB-064G beyond this ceiling, reaching sequential read speeds of up to 140MB/s — provided the host device and card reader both support UHS-I. Devices with slower interfaces cap the card at their own maximum throughput instead.

In real-world transfer scenarios, that speed moves approximately 1,000 photos per minute through a USB 3.0 card reader, based on SanDisk’s internal testing with images averaging 3.55MB. Meanwhile, write speeds trail read speeds, as they do with all flash storage — the card’s Class 10 and U1 ratings set the minimum write speed floor.

Speed Class Ratings Explained

The SanDisk Ultra 64GB carries three speed class designations, each targeting a different use case:

• Class 10 (C10): Sets a minimum sustained write speed of 10MB/s under the legacy SD speed class standard. This floor meets the baseline requirement for continuous Full HD (1080p) video recording at 1920×1080 resolution.
• UHS Speed Class 1 (U1): The UHS-I counterpart to Class 10, holding the same 10MB/s minimum write speed on UHS-I enabled host devices. U1 actively supports real-time Full HD video recording. That said, users shooting 4K should look elsewhere — 4K typically demands a V30-rated card with a minimum 30MB/s sustained write speed, which the SanDisk Ultra does not offer.
• Application Performance Class A1: Delivers a minimum of 1,500 random read IOPS and 500 random write IOPS. Rather than benefiting sequential transfers, this rating directly serves Android users who store apps or app data on external storage. A1 performance cuts app launch latency and accelerates loading of in-app assets — graphics, audio files, saved profiles, and permissions data — all of which depend on random I/O rather than sequential throughput.

Storage Capacity and the microSDXC Format

Unlike the 32GB Ultra, which uses the microSDHC format, the SDSQUAB-064G adopts the microSDXC standard — a format that covers cards from 32GB to 2TB. All modern Android smartphones, tablets, and Chromebooks read microSDXC natively. Older devices limited to microSDHC, however, will not recognise this card, so verifying host compatibility matters before purchase.

In practical terms, 64GB comfortably holds:

• Approximately 2,000+ photos at 24MP resolution (JPEG)
• Several hours of Full HD 1080p video, depending on the device’s recording bitrate
• A mixed workload of app data, downloaded media, WhatsApp content, music libraries, and documents — a combination that suits Android users juggling multiple file types at once

Beyond the card itself, the included full-size SD adapter extends compatibility to DSLR cameras, mirrorless cameras, Windows laptops with SD slots, and desktop card readers.

App Performance and the SanDisk Memory Zone App

The A1 rating on the SanDisk Ultra 64GB directly supports Android devices running version 6.0 and above that use adoptable storage — a feature that formats the microSD card as internal storage and folds it into the device’s native storage pool. Rather than functioning as a slow overflow drive, the SDSQUAB-064G actively participates in app performance through its 1,500 read IOPS floor.

Beyond adoptable storage, the card works with the SanDisk Memory Zone app (available on Google Play), giving users a single interface to:

• View and manage files across both internal and external storage
• Automatically route media files, downloads, and WhatsApp content to the microSD card
• Back up card content to linked cloud storage services

Together, A1 performance and Memory Zone support make the SDSQUAB-064G a particularly capable choice for users actively managing storage on mid-range Android devices.

Durability and Environmental Protection

To protect stored data across demanding conditions, the SanDisk Ultra 64GB passes testing against five environmental stress factors:

• Waterproof – Survives water exposure without data loss
• Temperature proof – Operates across -25°C to 85°C, with a non-operating storage range of -40°C to 85°C. This range covers Kenya’s climate from hot low-altitude regions to cooler highland conditions, as well as in-car environments where dashcams face direct sunlight and elevated cabin temperatures
• Shockproof – Withstands drops and physical impact
• X-ray proof – Passes through airport security X-ray scanners without data corruption
• Magnet proof – Flash memory architecture means magnetic fields leave stored data unaffected

These ratings apply to the card itself. The included SD adapter does not carry an independent durability certification.

Chromebook and Windows Laptop Compatibility

Moving beyond smartphones and tablets, the SanDisk Ultra 64GB explicitly supports Chromebooks and Windows laptops equipped with microSD or SD card slots (the latter via the bundled adapter). Chromebook users, in particular, gain practical offline capacity for Google Drive content, Play Store Android apps, and locally stored files — a meaningful addition on entry-level Chromebooks with constrained onboard storage.

Who Is This Card Best Suited For?

• Android smartphone and tablet users with limited internal storage – The A1 rating (1,500 read IOPS / 500 write IOPS) delivers faster app and media loading than non-A1 alternatives. Furthermore, the 64GB capacity gives substantially more headroom than the 32GB Ultra for users juggling both media libraries and app data at the same time.
• Full HD video shooters – The C10/U1 rating guarantees the 10MB/s minimum write speed needed for uninterrupted 1080p recording. However, the SDSQUAB-064G does not support 4K workflows — those require a V30-rated card with a minimum 30MB/s sustained write speed.
• Chromebook users expanding local storage – SanDisk certifies Chromebook compatibility explicitly, and 64GB provides workable offline storage for documents, downloaded media, and Android apps from the Play Store.
• Dashcam users – The wide operating temperature range (-25°C to 85°C) and continuous write capability combine to make this card reliable for in-car recording, even in vehicles that reach high cabin temperatures under direct sun.
• Travellers and mobile professionals – The five-point durability profile addresses the most frequent accidental damage and travel risks: water, drops, magnetic fields, and airport X-ray scanners. Additionally, the microSDXC form factor adds no meaningful weight or bulk to a bag or pocket.
• Buyers stepping up from 32GB – Users who have outgrown 32GB capacity but don’t need 4K recording or the premium pricing of the Extreme or Extreme Pro range will find the SanDisk Ultra 64GB a well-matched, cost-effective upgrade.