Hey i agree all the way.. Why should you have to spend $$$ to keep up software sequencers? it doesnt make sense..
I have very little experience with Cubase, but i know that a lot of people who have used cubase have switched to either Sonar or Logic for midi work, and just use Cubase to master audio.. My old specs kept one midi instrument in sync with Fruityloops barely. SB Live has no ASIO drivers, which make working with Midi almost impossible..
I upgraded about 2 months ago and got myself
P4 3g, 1Gb Ram, 80G hard drive, Audiophile 2496 running on Windows XP Professional
When using FLoops, for example, I need to have the master midi synced to the Audiophile Midi, otherwise bits fall behind sometimes (similar to your basslines falling out of time towards the end)..
Also, are you daisy chaining your midi in/outs? I know you have a midi sport, but if you have more than 2 synths in one chain, then you may have syncing problems no matter what your specs are.. know what i mean?
like i have my soundcard midi OUT going into my bass station IN. my bass station THRU goes to my MS2k IN, as well as using my bass station CV/GATE OUT into my 101 CV/GATE IN's...
hmmm.... i dunno how i can help you. i hope some of what i said might help.. otherwise when i get pissed off that nothing is working, i just reformat my computer and reinstall everything (although i usually lose a lot of files)
Anywayz Good Luck again, all the best