Any computers storage capacity does not increase performance. Read/write speads however do, but seeing as there is no difference to 3gig and 8gig read/write then the answer to your question is no.
As for RAM, this does increase performance based on both capacuty and speed (mhz). Although you can have as much RAM in the world, its pretty useless when you have a storage device running really slow that the RAM has to wait. Same applies to CPU's, GPU's etc etc.
Kev
