The fastest rubber? Really? Really! And nobody said anything worthwhile or sane? Well, except for Liten!
Where are Der_Echte and NextLevel when they are needed?
Okay, here we go: What rubbers are you currently using? You have said you are using the Donic Ovtcharov CarboSpeed. What rubbers did you have on it?
What level player are you? If someone gives you heavy backspin long to your backhand can you:
a) loop it with your backhand fairly easily?
b) step around your backhand and loop it with your forehand?
c) both of the above decided by tactical choice?
Most higher level players have a preference for some balance in the speed to spin ratio of a rubber. And would not consider speed without considering the speed to spin ratio of a rubber.
For example, there are a lot of pros who choose to use Tenergy 05 over the other Tenergy rubbers even though it is the slowest. It is the slowest but because it has the highest Spin to Speed ratio, you can swing harder, more safely and make your shot go faster and have more spin so that it arcs onto the table. So the slowest Tenergy allows you to hit the ball harder because it generates more spin and allows those shots to be safer.
A lot of the fastest rubbers have a lower throw angle because the speed is the higher factor in the speed to spin ratio. So a rubber with a higher speed in the speed to spin ratio will have a flatter arc and will require more control from the player to get the ball on the table, but those low arc, lower spin, fast shots will be lethal in the hands of someone with top level skill who likes that kind of arc. Trouble is, it makes it much easier to miss the table and for anyone lower than a pretty high level pro, it would also force you to take a much softer, less aggressive stroke.
Now way more top pros use rubbers with a high spin to speed ratio whereas, not so many top pros use a rubber with high speed to spin ratio.
The supreme example of this is in Liten's joke. Often when people are used to Tensor rubbers and they try DHS Hurricane 3 they think, "this rubber is sooooooo slow! Why do the top Chinese players use a rubber that is so slow?" The fact of the matter is that H3 is way up on the spin to speed ratio. Way more spin than speed. But look at what gigantic strokes the top Chinese players are able to make with those slow spinny rubbers! And notice, because of what powerful shots they take, the ball goes faster with the high spin, low speed rubber than the European players get with their fast blades and fast rubbers. Also, the top Chinese players are using blades that are an okay speed. But not blades that are anywhere near the fastest blades in terms of speed.
So, do you really want the fastest rubbers out there? I don't know. Perhaps you should try Stiga Calibra! That fits the category you seem to be looking for.
I would try Tibhar Evolution EL-P or Tenergy 05 instead. Better spin, good enough speed.