Hi Isabella,
master and sybsystemprocs are not hig usage databases. So from performance perspective you can leave them on filesystem devices.
Have you tested that raw devices are really faster in your environment? I've been at several different sites and my experience is that disk performance depends on the whole hardware setup. So for an environment X with storage y and controller z raw devices are faster; and for environment A with storage b and controller c filesystem devices are faster.
Regarding tempdb: it is also possible to put tempdb on a ram disk / tempfs. As tempdb is recreated when ASE is started, there is no need to store the data on disk. You have expand tempdb with "alter database" on tempfs.
After a reboot of the box the files are gone. So you have to create them manually with the "touch" command. Size 0 is sufficient, ASE will expand it during startup.
Here you might want to test the best number of devices for tempdb. A customer, I know, is using tempdb with 16 devices.
Best regards,
Juergen