Had 4G ram when I first downloaded v0.4.27.2. Very slow if it came up at all. After expanding to 8G, operation has been seamless even with upgrades...now running 0.5.3. Excuse me if I'm re-stating old material, there just seems to be many problems stated here that increased ram will take care of.
I'm aware that increasing RAM will make things better (and so will using an SSD instead of a HDD), but that isn't really a solution.
The big concern is whether the RAM requirements are scaling with time/blocks or just scaling with user adoption. If it is the former, then that is a serious problem (and a bug because there is
no reason why it
needs to be) because it will eventually be too much to handle for even serious servers (well I suppose perhaps not if we assume Moore's law to continue to hold since: given any k > 0, e^x > k*x for x >> 1). But my guess is that it is the latter.
Even then, from what I have seen the RAM demands of bitshares_client grow unnecessarily with the time it has been running (when syncing the blockchain to the present). Restarting the client and letting it resume sync from where it last started seems to make things better (for a time). This is a performance
bug that should eventually be fixed (I can completely understand if it isn't high priority though). As far as I can tell it only affects the client when the sync it is trying to catch up with the present block, and not when it has already synced and is simply running and maintaining the sync.
Obviously, even if these performance bugs were fixed, it is clear that the memory, CPU, and IO demands are never going to be trivial (especially as user adoption increases and transaction volume increases). So eventually very few people will be running full clients. And that is where a fully functional lightweight client comes in (it also is a necessity for mobile devices, which eventually
should have the same functionality as a client running on a laptop/desktop). My hope is that the performance of the BitShares full client can be kept reasonable enough for long enough so that we do not need to exclude those with computers with 4 GB of RAM and HDD from running the full client, at least until we have a feature complete lightweight client (that means voting and exchange functionality as well). Furthermore, I seriously hope the performance demand of the BitShares full client doesn't exceed the capabilities of computers with 8 GB of RAM and SSD (and even more preferably 4 GB of RAM and HDD) until we have a much better lightweight validation/security model than just trusting the light wallet server (I have discussed what I would expect
here).