Tune Performance by putting large tables into the KEEP Pool
You can put the table in KEEP Pool cache and this may have a positive impact on your queries. I have implemented it in my system for a 16 GB partition and we did get good performance gains.

However putting a table in cache does not mean that its data is loaded into memory automatically. 
It only means that since we are using a separate buffer pool for these tables, the data blocks that are loaded into memory are not aged out from the buffer as frequently as they would have if you were using the default buffer pool.

So in case your queries are fetching same data blocks repeatedly there will be lesser aging out and better performance gains. However, in case your queries are fetching different data blocks which are not present in the cache then you will be having some disk reads happening and old blocks may get aged out of bufer.

Also, have you evaluated RESULT_CACHE hint for yor query, in case you are not using GTTs you may be able to get good performance gains from that also.