booting off secondary hddcaddy in laptop?

Can I put a ssd in a hdd caddy and boot off it in a laptop? If so It is a sata 2 port.will I lose that much speed? Also Trim should still work on the secondary port?
Machine specs

sandy creek I7 2630 qm Intel3000/Radeon6770M, using Leshcat Labs driver 15.4 dynamic switchable graphics.. 16GB ram Intel 530 240 ssd or Seagate SSHD 1TB as boot .depending on my mood for speed or capacity. I would move my 2TB seagate to primary port.. THe reason for this is easy switching of boot drive by use of caddy.

Since we don't know what laptop, no idea.

It should work yes, assuming it is connected to a normal chipset sata port.

There are many laptops that it is not, but connected to some sata 1 thing, or even a cdrom only port. Generally in these they just didn't connect the second port to anything, or used it for an msata device instead, so since it wasn't available they did something else for the laptop port.

So without the exact model number, and google, no way to know. Though, these days, it *should* work.

What works best if your laptop supports it is to have an SSD in an mSATA or M.2 slot (most laptops from the past 2-3 years have mSATA available) and then drop a nice big HDD in the 2.5" bay.

Depending on the model there will either be an explicit option to boot from mSATA or you can trick it to do so either by having no other valid boot devices or putting a boot loader (like grub) on the 2.5" drive that points at the mSATA drive's OS installation.