Too fully take advantage of optiminer's improvements you need a modern cpu that supports aes and avx2. For me on a E3-1240 i managed to double the hashrate with it. ( using 4 cores , on ubuntu 14.04 )
In your case using 2 cores yields more hash, the higher the combined hashrate the better. ( i assume you have an old dual core cpu )
Do I need both (AES and AVX2) instruction extensions for hodlminer? I'm mostly confused as to how my hash rate drops when using hodlminer on one thread. My computer supports AES but not AVX2 (only AVX1.1), is this part of it?