The presentation of the new flagship Android handset focused on the functions, with Samsung talking about the heart rate sensor and the accessories, as well as battery saving features and the 16-megapixel camera.
Although it was confirmed that it would offer a 2.5GHz quad-core processor, an infographic from Samsung late last night shows the progression of the Galaxy S handsets through the generations, culminating in the Galaxy S5, with both quad and octa-core versions illustrated.
Samsung hasn't pushed the details of the hardware as strongly as some manufacturers, focusing on function over hardware. It wasn't until Qualcomm confirmed that it was Snapdragon 801 that we knew what the 2.5GHz chipset was.
The source page (linked below) appears to have been taken down, but we still had the infographic in our RSS feed, so we've included it below.
We can only assume that this will be an Exynos octa-core version that appears in some territories, in a similar fashion to the Samsung Galaxy S4, although note the disclaimer: "subject to change without notice or obligation" on the bottom of the infographic.