TK, shut up about taking me off the world records or I'll go beat your shit times by several minutes vs 5/6 cpus on EF and F. <3
Also, I watched you try 5+ times vs 6 cpus on bne/f last night and you got crushed.
As for the F vs EF debate when it comes to playing computers, F is definitely harder and there's at least a couple reasons as to why this is so.
1) The CPU's actions are automatic, while human player's have to manually do each action as quick as they can. The faster the speed and the larger your base gets the less of it you can manage within a given amount of time, because everything is in motion - and on Fastest battles are faster, wood chops faster, buildings finish faster, etc etc. So, in essence the faster the speed the more you're falling behind. Seeing as the speed difference doesn't effect computers, because their actions aren't delayed, you're inevitably falling more behind on F than you're on EF. You don't notice this to be true because you just assume you're losing on F because it's not your speed. So I encourage you to go ahead and play 7 CPU's at 1 or 2 speeds lower than EF and you should notice that the lower the speed gets the easier it gets.
2) CPU's don't have any real UC tactics, and humans do. We're able to exploit this advantage to a greater degree on EF, as it both far easier to UC on EF, there is more "time" to UC on EF, and there's many more practical UC maneuvers on EF than on F.
I'm sure there are other reasons why too. F is unarguably significantly harder. I'm top tier at both speeds, and playing 7 cpu's on BNE/EF is a cakewalk while 7 on BNE/F can be a challenge.