In a first for iPhones, Apple says the iPhone 8 and 8 Plus can "fast charge" from 0 to 50 percent in 30 minutes. That is, as long as you have a specific kind of Apple power adapter (29-, 61-, or 87-watt) and a USB-C to Lightning charging cable -- both of which are not included.

Still, it's a nice bonus if you have the right equipment, but most iPhone users have noticed that earlier iPhone models would generally charge faster than normal if you used a higher-wattage plug than the one that came in the original box. So the question remains: How much faster does the iPhone 8 Plus charge compared to the iPhone 7 Plus? We ran our own tests to find out.

A video posted to YouTube shows an iPhone 7 Plus charging nearly as fast as an iPhone 8 Plus using Apple's 29-watt power adapter and a USB-C cable.

Even before we began testing, that didn't seem to make any sense. Fast charging requires special controllers inside of the device and power adapter to transfer more electrical power. On Android phones, if you use a power adapter that's not certified for Qualcomm's Quick Charge technology, it won't charge up your device at the faster advertised speeds.

So we got to work: Using Apple's advertised accessories (for our tests, a 29-watt power adapter), we fast charged up a new iPhone 8 Plus and year-old iPhone 7 Plus that's only been charged up every few weeks. Generally speaking, both batteries are in great condition.

In the YouTube video we saw, an iPhone 8 Plus charges up to 45 percent in 35 minutes and to 42 percent on the 7 Plus in the same amount of time. Though the YouTuber claims he used legitimate accessories, we got different results in our own tests.

In our tests, both phones were drained to 0 percent, and then were put in Airplane mode and brightness lowered to 50 percent after they automatically turned on. Here are our recorded charging numbers:

iPhone 8 Plus

• 27 percent in 15 minutes

• 54 percent in 30 minutes

iPhone 7 Plus

• 15 percent in 15 minutes

• 29 percent in 30 minutes

Per our data, the iPhone 7 Plus charged about one percent per minute, while the 8 Plus gained 1.8 percent per minute.

In other words, using a fast charger on the iPhone 8 Plus really does charge it up much faster than on the iPhone 7 Plus -- 86 percent faster, in fact.

Going to 100

The YouTube video also shows the iPhone 8 Plus charging to 100 percent in 2 hours and 11 minutes and the iPhone 7 Plus to 100 percent in an even faster 2 hours.

So we drained both iPhones down to zero and charged them both to full and here's what we got:

iPhone 8 Plus

• 100 percent in 1 hour and 50 minutes

iPhone 7 Plus:

• 100 percent in 2 hour and 32 minutes

As you can see the iPhone 8 Plus still charges up faster versus the iPhone 7 Plus.

YouTuber and Mashablefriend Danny Winget conducted his own fast charging tests between an iPhone 8 Plus, Samsung Galaxy Note 8, OnePlus 5, and HTC U11.

His results? The OnePlus 5 charges up the fastest with its own proprietary "Dash Charger". The HTC U11 comes in second place and then the iPhone 8 Plus in third. Most surprising of all was the Note 8, which lagged in last.

For the iPhone 8, he got basically the same result: 53 percent in 30 minutes.

While Winget could've stopped at 30 minutes, he added another 30 minutes to the clock to see how close to full the phones would get. Needless to say, the results were the same. The OnePlus 5 was the only phone that nearly charged up to 100 percent, followed by the HTC U11, iPhone 8, and the Note 8.

So what have we learned? Apple's not lying and you can't believe every YouTube video "test" shared online. The iPhone 8 Plus's fast charging is legit speedier, whether it's charging up to 50 or 100 percent.

If you want the faster charging, the iPhone 8 and 8 Plus are the only iPhones that can do so for now (the iPhone X will also support it when it launches in November).