2 min if speed of 15 billion achieved and if i write private key and corresponding public key
Are you looking for uncompressed or compressed?
Since I do not know your purpose in this, I can't help you to shorten the pubs.
Regardless, 20 million priv keys and corresponding pubkeys should only take up about 2.5Gb in storage space.
The purpose is to make precomputed tables , nothing else. 😁 . Uncompressed pubkeys are fine since i found that it would be beneficial to store them as hash only which eventually will save space too and private keys can be found later by index. No need to save them. I learned it from jean Bsgs Code. It uses 25 bits to save the baby steps. And i think its same as sequential pubkeys if the sole purpose is for making a hash table.
But still i didnt get any idea of how the 15 billion per min speed can be achieved.
I have no idea either...no way to write 15 billion in one minute, IMO, at least not on my hardware. Best I could do was about 200K a minute. Let me better explain. Normally when I do a search/look for keys, whether random or sequential, one of my GPUs will get 200MKey/s, but when I try to write the results, it drops to 0.1MKey/s because of the writing to file/RAM. So the bottleneck to me, is all in the CPU writing to file.