Amazon’s Kindle has been a favorite e-reader for a long time, and the latest Kindle Paperwhite is no exception. And today, you can get a brand new Paperwhite for just $100Remove non-product link, down from a list price of $130 and just $10 off its all-time low.

This sleek Kindle Paperwhite is designed to come along wherever you go. Just like a paperback book, it’s thin and light, but the Paperwhite is also waterproof, with a glare-free 300ppi display for clear visibility even in bright sunlight. Long-lasting battery will keep it up and running for weeks on a single charge, while 8GB of storage provide plenty of space for books, magazines, and more. If you’re more of a listener than a reader, this Paperwhite has you covered; you can tune into Audible with Bluetooth-enabled headphones. You can also switch between listening and reading easily—the Paperwhite will save your spot and help you pick up where you left off.

We gave the all-new Kindle Paperwhite 4.5 stars out of 5 in our review for its sleek design, Bluetooth connectivity, clear display, and huge selection of content options.

[ Further reading: The best DVRs for cord cutters ]

[Today’s deal: Amazon Kindle Paperwhite for $100Remove non-product link]

Reolink’s latest home security camera isn’t really a new model, but more of an upgrade of an older one. The Reolink C2 Pro retains the same body as the the C1 Pro, but improves its image quality with a five-megapixel camera that delivers 1920p resolution.

According to Reolink, this results in videos that are 1.3-times clearer and sharper than 4MP cameras like the C1 Pro, and 2.4-times clearer than competitors that deliver 1080p resolution. The C2 Pro retains its sharpness even when you use its 3X optical zoom.

Many of the other features of the C1 Pro are still here: A ring of eight infrared LEDs around the camera’s lens provides up to 40 feet of night vision. The camera also includes an integrated microphone and a speaker for two-way communication, and it supports motion detection with push notifications. It can rotate 355 degrees horizontally and 105 degrees vertically, and supports dual band Wi-Fi for stronger network signals.

You can save motion-detected video clips locally to microSD card (cards with up to 64GB of capacity are supported), or you can upload them to an FTP server. You can also enable 24/7 continuous recording by connecting the camera to Reolink’s 8- or 16-channel NVR, sold separately for $230 and $330 respectively.

Reolink

Setup

Though the C2 Pro operates over your Wi-Fi network, you must first connect it to your router for initial setup (an ethernet cable is provided). Once you do this and plug in the power cord, you scan the QR code on the bottom of the camera using the Reolink app and follow a few onscreen prompts to connect it to your wireless network.

The pear-shaped camera can be set on a table or shelf or mounted to a wall using the included hinged bracket and mounting hardware. The bracket can be angled up to 90 degrees and locked into place.

The app

Michael Ansaldo/IDG

One you add the camera in the Reolink app, it appears on the device page with any other connected Reolink cameras you have. You an adjust various settings from here, including video quality, recording method, and storage preferences. Most importantly, this is where you turn on push notifications for motion events—it’s turned off by default—and set a recording schedule if you don’t want the camera capturing motion events around the clock.

Selecting the C2 Pro from the device list opens the camera’s home screen. Along with the live-stream pane, you’ll also find a toolbar with buttons for all the camera’s controls—play/pause, record, and snapshot buttons—plus a toggle for the camera’s resolution, and another button for viewing the feed full screen.

At the very bottom of the screen are a push-to-talk button, pan-and-tilt controls, a playback button that accesses your library of videos, and a button labeled “Clip.” This last one opens a screen capture of the camera’s current view at the bottom of the screen, with a small box overlaying it. As you drag the box to different parts of the image, a zoomed-in view of that crop appears in the camera’s live view pane.

Performance

True to Reolink’s claims, the C2 Pro delivers a remarkably clear, sharp image. The wide viewing angle allowed me to take in most of my living room even without needing to pan the camera, but this also resulted in a tiny bit of image bending around the edges. It also reproduces colors as far more vibrantly than they are in reality. That’s not really a problem, except that parts of the image took on an orange cast from whatever light fixture I had turned on.

The pan and tilt controls include a directional pad, zoom, and focus buttons that let you fine-tune up-close shots. I found that particularly helpful when I was getting successive motion alerts and couldn’t figure out what was setting them off. I zoomed in on a pile of blankets on my living room floor and found one of my cats nestled in it, cleaning herself.

Michael Ansaldo/IDG

Yesterday we spotlighted a great gaming rig from Walmart, and today we have an even better one. The retailer is selling an AMD-based Cybertron GameStation that would be awesome for 1080p gaming for $570Remove non-product link. Unfortunately, Walmart’s delivery and pick-up times for this rig are scheduled for Monday, February 11, so that means you won’t be able to use this PC in-time for the launch of the The Division 2 private beta this weekend, but it’ll be in your hands well before the game’s official release in March.

Walmart’s Cybertron GameStation features a quad-core, 3.5GHz Ryzen 3 2200G APU, 8GB of RAM, a 1TB hard drive for storage, and a 120GB SSD boot drive. AMD’s APUs are surprisingly decent for gaming, but there’s no beating a discrete graphics card. This particular rig is rocking a 4GB AMD Radeon RX 580, but you’ve still got a great rig for 1080p gaming with all the settings maxed out. And you might get some decent 1440p performance as well, even if it’s not quite as good as the 8GB RX 580.

This is also your last chance to get in on AMD’s Raise the Game Bundle, which ends on Saturday. If you buy this desktop before then you are eligible to get two free games for free from among Devil May Cry 5, The Division 2, and Resident Evil 2.

[Today’s deal: Cybertron GameStation for $570 at WalmartRemove non-product link]

You just want to buy an SD (secure digital) card or microSD card for your DSLR, dash cam, drone, smartphone, or tablet. But one size doesn’t fit all. If the confusing array of memory card logos and specs has you pounding your head against a wall, we understand. We’ll give you the quick answers for most common memory card uses. (Pro tip: Check your device’s manual for memory card recommendations.)

If your needs are very particular, we’ve also delved deep into SD card standards to help you understand the difference between Class 10, V30, UHS-I, A1, and U3, so you can make the right choice for any device or purpose.

Secure digital (SD) card cheat sheet

Here are the short answers to which SD card to buy for which purpose:

• Best SD card for video use: Concentrate on the Speed Class rating given for your device. Generally, a Class 10 card works for 4K video at 30fps. For anything higher, it’s recommended to invest in V30 and up. Go here for more details.
• Best SD card for a GoPro Hero: For Hero 4 Black and older, a Class 10-rated card is generally fine but newer cameras such as the Hero 7 Black should be fed with U3 or V30-rated cards. Go here for details.
• Best SD card for a DSLR: Choose a card based on its maximum write speed. While there’s no logo for that (thank god), 40MBps to 50MBps is typically good enough for most consumer and even some prosumer DSLRs. Go here for more details. 
• Best SD card for an Android phone or tablet: Because of limitations in how these devices handle SD storage, storing apps on a card may frustrate you—though an A1-rated card may help a little. For storing photos or video, pay attention to the stated write speed. Go here for more details. 
• Best SD card for a Nintendo Switch: For the best deal, skip the “official” card and buy a high-capacity card that works for your budget. Go here for more details.
• Best SD card for a dash cam or nanny cam: Ignore the write speeds and X-ratings and go for one that touts “High Endurance.” Go here for more details.

SD speed class marks explained

One of the most confusing specs on SD and microSD cards is the dreaded “speed class” mark. For the most part, it’s pertinent only to recording video. Let’s say that again: It’s mostly intended for video.

Unlike with still photography or file storage, an occasional pause in data writes isn’t a big deal, as the camera or device should just pause and pick up where it left off. Video, however, requires undisturbed writes, because the stream can’t be easily paused on most consumer hardware.

The most familiar of these speed class designations is the basic numeric code of 2, 4, 6, and 10 that have been around since the mid-2000s. The number denotes the minimum write speed without a fatal (for video) disruption. A Class 4 card will write at 4MBps, for instance, and a Class 10 will write at 10MBps. 

SD Association

This was fairly straightforward until the U1 and U3 UHS Speed Class marks were introduced in 2010 and 2013, respectively. U1 and U3 indicate a respective minimum of 10MBps or 30MBps write speeds. Both also support a faster ultra-high-speed (UHS) bus.

Amazon

To help muddy things even more, in 2016, a new Video Speed Class mark was introduced to increase speeds for even higher-resolution cameras and devices. Video Speed Class includes: V6, V10, V30, V60, and V90. As you can guess, the number denotes the guaranteed write speed in MBps (which in some cases can be lower than a card’s maximum write speed.)

There are actually deeper technical reasons for why you might prefer a Class 10 card (or an even slower Class 6 card) instead of a V90 card for standard-definition video (think 1990s’ era 640×480), but generally, if the card maker did its job, writing even standard definition video won’t be an issue.

The part that drives consumers batty is that all three speed class ratings are still in active use on memory cards today. Many cards carry multiple speed class markings. Even more confusing are cards like the Toshiba pictured here: If V30 is rated at 30MBps writes, why does it only have a Class 10 rating, which indicates a 10MBps write speed?

Which SD speed marking is the ‘best’?

Believe it or not, the markings on the card and package aren’t there to confuse you, but to help you. Ideally, you’d look at your action cam or nanny cam’s manual, and see that the maker recommends a Class 6, Class 10, V10, or U3 card, and buy a card with that marking.

In fact, that’s the best way to use the speed-class markings properly. The problem is you probably don’t know what your camera or doohickey recommends, so you end up trying to find out what C10, V30, and U1 mean from a browser on your phone while two kids tug on you to go to the toy section.

The only real pitfall to watch for is paying (probably overpaying) for something you don’t need or can’t even use. For example, putting a V30 card in a device that requires Class 10 is about as wasteful as filling up a minivan’s tank with high-octane gas instead of plain, old unleaded.

Seen in that light, the chart below from the SD Association actually starts to make more sense. If you don’t know what your device recommends, you should probably look at the video standard it records at on the right of the chart below, and buy the cheapest name-brand card that corresponds with the speed class.

For example, say you have no-name action cam that records at 4K 30fps. Based on the chart below, a Class 10 card should work, with a V10 card being mostly interchangeable. If you have a creepy nanny-cam in your kid’s bedroom that records grainy 1080p 30fps video in night mode, a Class 6 should work just fine.

SD Association

What’s the best SD card for a 4K video camera or a drone?

The guidance above, however, assumes fairly low frame rates of 4K at 30fps, or 1080p  at 60fps. It doesn’t actually take into account newer cameras that record at 120fps.

Unfortunately, there’s no general guideline, so the fallback is always to refer to the manual or manufacturer’s website. If you don’t know, it’s safest to opt for more speed. For 4K at 60fps, for example, you might want to reach for a faster V30 or U3 card. If you’re recording 8K, surround video, or multiple data streams at once (GPS data for example), you should probably opt for a V60 or V90 card.

But again, always check what the manufacturer recommends. You may be surprised at what works. Mavic’s Phantom 4 Pro V2.0 drone, for example, can record at up to 4K and 60fps on a Class 10 card—but it must be rated at 15MBps write speeds. So something like Transcend’s High Speed cardRemove non-product link would work. 

Amazon

What’s the best SD card for a GoPro?

As our guidance goes for all devices: Read the freaking manual for what’s recommended for the camera before you go out and buy a memory card. This can save you from buying a card too slow (potentially losing video) or from spending too much money on a card your camera can’t fully exploit.

In the case of GoPro’s popular Hero cameras, much of what is recommended will depend on the vintage of your camera. The very old Hero 3 cameras, for example, don’t support more than 64GB capacity, and with their maximum of 4K video at 15fps, a Class 10-rated card, such as the SanDisk Extreme microSDXC UHS-1Remove non-product link should work just fine.

Step up to the newest Hero 7 Black, which can record 4K video at 60fps, or 1080p at 240fps, and you’ll need a U3 or V30-rated memory card memory card like the Samsung 128GB EVO SelectRemove non-product link.

GoPro’s manual nicely lists cards that it has vetted for each camera going back to the original Hero.

What’s the best SD card for a DSLR?

There’s a very important thing to remember: The Speed Class discussions above are mostly pertinent to video use, where you cannot ever have the card stall while writing video. Modern digital cameras aren’t so sensitive. If there’s a slowdown while writing 40 images, the camera’s internal memory buffer can hold the pictures just a bit longer while they’re written to the memory card. So, for the most part, even super-budget SD and microSD cards will yield good results for the average photographer.

The only real problem is when that buffer is full from taking, say, 75 images of the kids blowing out the candle. Once that happens, the camera won’t take pictures until the buffer is clear. Sometimes, the camera will actually slow down the picture-taking from 4fps to 1fps while clearing the buffer.

Amazon

For these photographers, you’ll want to pay attention to the explicit write speed of the card. The SanDisk Extreme ProRemove non-product link pictured here, for example, can write at 95MBps. There is no industry logo or marking for write speed, but we’ve found that most cards that state the write speed are bragging (sincerely) about a tested capability.

If you’re choosing between cards for photography and you have a choice of V30, or V10 (or Class 10), the V30 will likely outperform the Class 10, at least by the specs.

Some card makers will actually express the maximum write speeds as an “X-rating,” such as 400X. This is the write speed of the card expressed by CD-ROM speeds. Every 100X denotes 15MBps. For still use, you’ll want a higher X-rating if you like to take a lot of pictures in a row.

Tested: SD performance tested in a DSLR

How much does the write speed matter in actual use? We did some quick tests with four grades of SanDisk microSD cards in a Sony Alpha A7R II camera. We timed how long it took the camera to write 10 RAW+JPEG files, each about 42MB. For this test we used a 256GB SanDisk ExtremeRemove non-product link, a recent-production 400GB SanDisk UltraRemove non-product link card, a 3-year-old 32GB SanDisk UltraRemove non-product link card, and a nearly generic, basic black 32GB SanDiskRemove non-product link card. Each card’s markings are noted on the chart below. Only the SanDisk Extreme had a rated write speed of 90MBps. Each card was formatted in camera prior to testing.

IDG

There are three takeaways from the results you see. The most obvious is that there is a world of difference between the generic 32GB SanDisk card with no markings and the older 32GB SanDisk Ultra card. There’s also a galaxy of difference between the older 32GB SanDisk Ultra card and the new 400GB SanDisk Ultra card. While some of that is the newer memory chips in the 400GB card, some of it is also the capacity. Memory cards today are very similar to SSDs, where some of the capacity is set to cache reads and writes. What that means is a 400GB SSD or memory card, is generally going to be faster than a lower-capacity version of the same model. As the large card reaches full capacity, cache gets smaller as it’s turned into storage, and performance will drop.

Next page: More microSD card testing and buying advice for Android devices, Nintendo Switch, and dash cams.