Difference between Exynos and Snapdragon processors in Samsung devices

If all the talk about the two different versions of Samsung devices has you scratching your head, this little summary should help to clear things up a bit. Since the Galaxy S2, Samsung has been releasing two different versions of their flagship devices with different processors for different markets: the octa-core Exynos processor and the quad-core Snapdragon chipset. So why does Samsung do this and what is the difference?
 Snapdragon 835Exynos 8895Snapdragon 821Exynos 8890
CPU CoreSemi-custom ARM CortexCustom + A53KryoCustom + A53
CPU Config4x 2.45GHz Kryo 280
4x 1.9GHz Kryo 280
4x 2.5GHz Samsung M2
4x 1.7GHz Cortex-A53
2x 2.35GHz Kryo
2x 1.6GHz Kryo
4x 2.3GHz Samsung M1
4x 1.6GHz Cortex-A53
GPUAdreno 540Mali-G71 MP20Adreno 530Mali-T880 MP12
RAM2x 32-bit LPDDR4X
1866 MHz
LPDDR4X2x 32-bit LPDDR4X
1866 MHz
2x 32-bit LPDDR4
1794 MHz
FlasheMMC 5.1/ UFS 2.1eMMC 5.1 / UFS 2.0eMMC 5.1/ UFS 2.0eMMC 5.1 / UFS 2.0
Camera support32MP single / 16MP dual28MP single / 28MP + 16MP dual rear28MP single / 14MP dual24MP rear
Video capture4K UHD @ 30fps4K UHD @ 120fps4K UHD @ 30fps4K UHD @ 30fps
Video playback4K UHD @ 60fps,
10-bit H.264 (AVC),
H.265 (HEVC), VP9 codecs
4K UHD @ 120fps,
HEVC (H.265), H.264, VP9 codecs
4K UHD @ 60fps,
10-bit H.264 (AVC),
H.265 (HEVC)
4K UHD @ 60fps,
264 (AVC),
H.265 (HEVC)
Modem1000Mbps down,
150Mbps up
1000Mbps down,
150Mbps up
600Mbps down,
150Mbps up
600Mbps down,
150Mbps up
Process10nm FinFET10nm FinFET14nm FinFET14nm FinFET

In 2017 we’re back to a familiar battle of the octa-core processors, albeit with both Qualcomm and Samsung opting for custom CPU cores this time around. We can’t say for sure which will be faster without some hands-on time, but the two companies are touting similar performance and energy efficiency improvements over last year’s close fought battle.
The Snapdragon 835 is apparently offering around a 20 percent boost to performance over the 821, while Samsung touts up to a 27 percent improvement with its Exynos 8895 from the 8890. Both companies have moved over to new CPU designs this year, although Samsung’s naming convention and PR hints at a revision rather than a complete refresh. The Kryo 280 is a new semi-custom ARM design that Qualcomm is using for its performance and energy efficient cores, while Samsung is designing its own big core for use in a familiar big.LITTLE setup, having licensed ARM’s ARMv8 ISA (Instruction Set Architecture). We don’t know the exact changes and improvements made to the internals of these two chips, but it appears that improving power efficiency has been a key goal at both companies.

Why Samsung uses two different processors

For starters, the Exynos chip is actually made by Samsung, the Snapdragon by Qualcomm. There's obvious cost savings involved in making your own chips, but a lot of it also has to do with markets and existing support. The Exynos chips usually make their way to Asia while Europe and North America get Snapdragon variants, although sometimes these things change. For example, the European Galaxy S3 was the Exynos variant and the Galaxy Note series brings Exynos chips to the US.
Part of the reason is to do with the supply chain. Samsung is easily the largest manufacturer of smartphones in the world by volume, and making chips to satisfy Samsung's demands could easily be the sole focus of a chip-maker. Likewise, dependency plays a part too: if there's problems at Qualcomm, Samsung can step in and equip a market with Exynos chips.
The split also allows Samsung to attack the market on two fronts and establish what works best and why. Not to mention that there is reportedly an existing contract between Samsung and Qualcomm that both sides are still committed to. In any case, it is unlikely that Samsung could produce enough Exynos chips for all of their devices even if they weren't tied to Qualcomm.