Samsung usually produces both Exynos and Snapdragon variants of its flagship phones, the former mostly used in non-LTE versions. However, the company didn't mention Exynos at all during the Galaxy S5 event. Now Samsung has gotten around to announcing two new Exynos 5 chips, one of which is probably going to be in the GS5.
The Exynos 5422 is a small spec bump over the 5420 announced last summer. It consists of four Cortex-A15 cores and four Cortex-A7 cores in a big.LITTLE configuration. The speedy A-15 cores run at 2.1GHz, while the efficient A7s are clocked at 1.5GHz. This chip supports Heterogeneous Multi-Processing (HMP), so all eight cores should be able to operate at the same time. Despite having hardware support for HMP, the 5420 likely hasn't shipped with it enabled. Thus, the 5422 could be the first Samsung octa-core to make use of HMP. It rocks the same ARM Mali-T628 MP6 GPU that was found in last year's Exynos 5 Octa.This is probably the SoC that will be found in 3G versions of the Galaxy S5.
The new Exynos 5260 might be more interesting, even though it isn't as powerful. This six-core chip is making its debut in the Note 3 Neo. It comes with two Cortex-A15 cores (1.7GHz) and four Cortex-A7 cores (1.3GHz) in the big.LITTLE setup. Like the 5422, it supports HMP and should ship with it active. The GPU isn't currently known, but it might be the Mali-T624. This chip could provide a great value for the performance.
On the less sexy end of the tech spectrum, Samsung also detailed its updated camera CMOS sensors. The 16 and 13MP ISOCELL sensors have increased light sensitivity and "30 percent decrease in crosstalk; 30 percent increase in full well capacity; and 20 percent wider chief ray angle." Presumably this is the camera sensor used in the GS5. Lower power WiFi and 45nm NFC chips are also on the table from Samsung going forward.