Can HP Proliant server be set to use no RAID?

No.

This is not possible.

The HP ProLiant DL380 G6 isn't a new server, though. It's three generations removed. If you're trying to use this for vSAN, don't. If it's any other situation where you need access to the RAW disk devices, you should purchase a dedicated SAS HBA from LSI or an HP-branded LSI controller. This can then be connected to the backplane and is compatible with VMware.

Same rules for ZFS, Hadoop, Storage Spaces, vSAN, etc.

I'm really curious about what you're doing, though.

If spinning disk performance is an issue, you really do need a Flash-backed Write Cache module and RAM for the RAID controller. Can you explain your problem in more detail?