Even if you're streaming samples from disk, there will always be some loaded into ram, on top of your applications and OS. This is one case where 64-bit OS rules in the area of addressable ram (128 gigs!). Kind of like how gigasampler handles samples even if they use disk streaming technology, there are always samples loaded into ram. From what I've been able to gather, it's like the first few seconds of a sample are loaded as a sort of buffer since the HD naturally is slower than reading off ram.
As for your swap file size, the norm is usually 1.5 times the amount of available ram, but that became obsolete when it became possible to have gigabytes of ram. I say keep your swap file static at 1 gig, but try to use partitioning software that allows you to partition specific areas of the HD, specifically the outer edge of the platter. Create a small partition there big enough for the swap file (maybe a couple of gigs), and assign the swap file completely to that partition. The rationale for the outer edge is because it is the fastest part of the HD, hence, data transfers are much faster than in other areas of the disk.
