Build Start?

This could be my first build day or not. I decided to try and rip some 20x32(mm) and 20x45(mm) stringer material out a piece of 2x4 (inch)Douglas Fir I picked up last week. My cheap table saw worked OK but it slowed going through that fir compared to spruce or pine.

I did buy vertical grain fir but when cutting out the stringer pieces the grain is as shown. Can anyone tell me if this wood is stronger in one grain orientation vs the other? The middle piece, 3rd from left is destine to be the lower hull outside stringer which will be scarfed to the 5th from left once I trim it down a bit.