Not to mention there's been instances where Flash was moving and the whole world was frozen I believe characters like Wonder Woman were frozen and Superman sped up his senses to talk to Flash.
Was powergirl just fighting because flash could have been there punching someone in the face and superman could have did the same speed feat. Powergirl was not even trying to speed. Also when flash fought Zoom at light speed, Superman was a frozen statue too.
A better question would be, does Powergirl have speed feats to put her on par with Superman's speed feats. If you want the easy answer no she doesnt.
Neither does anyone else on the list minus Flash who exceeds Superman in speed. I think Billy is the closest given he scales off Superman due to lack of appearances.
Flash was speed amped when he fought Zoom by the way. He got speed from Bart and Jay. Regardless Flash is faster than Superman. I'm just saying Supes has the type of speed where the whole world is at a standstill and he could have conversations and discussions. Noone here but Flash has that type of processing and interaction speed.
Then he used Jesse Quick's speed formula which makes time stop for Flash. That's when Superman was frozen compared to him. He was beyond lightspeed at that point.
In my opinion (and since we are discussing comics, it is all subjective opinion), comparing high-level speed (or high level anything) in comics will always be problematic due to the mix of subjectivity and relativity. Subjectivity of the writer and reader, and the difficulty of relatively comparing high level speed. This, it quickly becomes a pure fan selection poll.
Take for example Quicksilver. Super fast, and last night saw he could move at high supersonic speed. At say Mach 7, a human sized object would be so fast that he would be less than a humming blur from a distance, and closer the flash of a shadow.
However, in WW3 we saw Black Adam moving at Mach 500! Assuming Captain Marvel and Adam are analogous (yes, I know different gods and all that, but they are considered analogous) that shows a tremendous speed difference. So large that one could not compare QS with any primary Shazam-imbued character (e.g. CM and BA). Maybe not even the secondary Shazam-imbued characters like Mary Marvel. The speed difference is too great.
And then we get to Kryptonians, where even Superboy Kon (who is not even a pure K) was shown transversing the globe in like a joke.
And finally the Speedforce-imbued characters that can do speed feats that, in aggregate, don't have much competition. Maybe some of the crazier things the Silver Surfer has done, but in any case not much competition.
It would be difficult to rank a primary Flash against a primary Shazam type, even though a primary Shazam is ridiculously fast. That's just as an example. Imagine now against QS?
if you were standing 300 feet apart from all of them, and told them to run toward you, they would all appear to arrive at exactly the same time. To see a slight difference would probably require for you to be tens of kilometers away, and even then the difference would be between QS and the others (where four of them would seemingly materialize, and QS would come a short while later). From there it gets difficult.
I'd say that a true ranking would never have QS at 20-50 of a Flash type ...maybe he'd be at around 5, maybe less.
What might be even more controversial is what I think the gap is between a fully trying Superman and a Shazam character. It is a big gap.
Or what I think is the gap between a primary Flash going all out and a Kryptonian (also larger than many would be comfortable with).
In both cases, I would say the gap is greater than that between Quick Silver and Captain America in speed.
And then we get back to subjectivity. Just an opinion