Split Backup of MSSQL VS Stripe Backup of Sybase ASE
Any speedup in a striped backup will come from using multiple IO channels.  If all the files are in the same storage location it won't be any faster.

Using multiple CPU cores to process a backup probably won't help, as backup is extremely simple.  And a single CPU core can saturate the storage subsystem with backup pages.

You can see this for yourself with any big database, by writing the backups to the nul device:

set statistics time on
go

print '

single backup'


backup database AdventureWorks
to disk = 'nul'
go

print '

striped backup'

backup database AdventureWorks
to disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul',
   disk = 'nul'


outputs

single backup

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.
Processed 651384 pages for database 'AdventureWorks', file 'AdventureWorks2017' on file 1.
Processed 2 pages for database 'AdventureWorks', file 'AdventureWorks2017_log' on file 1.
BACKUP DATABASE successfully processed 651386 pages in 2.837 seconds (1793.779 MB/sec).

 SQL Server Execution Times:
   CPU time = 203 ms,  elapsed time = 2877 ms.
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.


striped backup

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.
Processed 651384 pages for database 'AdventureWorks', file 'AdventureWorks2017' on file 1.
Processed 2 pages for database 'AdventureWorks', file 'AdventureWorks2017_log' on file 1.
BACKUP DATABASE successfully processed 651386 pages in 4.023 seconds (1264.964 MB/sec).

 SQL Server Execution Times:
   CPU time = 499 ms,  elapsed time = 4123 ms.