burgerproduction
To add my 2 cents:
I'd put the OS, programs, FXs and Samples on the SSD and have an external HDD linked via your SATA connector as the recording drive. The reason for this is that an SSD has a limited number of writes over its lifetime. Accessing samples doesn't require any writing (unless you bounce/freeze the track) so you SSD will last longer if you are only reading files. 
I record live instruments and the huge file sizes and multiple takes would exhaust the SSD more quickly. HDDs don't suffer from this as you can write/erase/write to them an infinite number of times without effect. The connection speed via SATA is more than fast enough to accomodate read/write speeds for the audio tracks, while the SSD will boost the performance of the programs and VSTs.
Hope this makes sense.

Interesting. 
 
<<I'd put the OS, programs, FXs and Samples on the SSD and have an external HDD linked via your SATA connector as the recording drive.>> When you say "have an external HDD linked via your SATA connector," not sure what you mean. I will have the existing HDD still installed, along with a planned new SSD. Can you define "linked"? Do you just mean available for use as a recording drive?

You are partitioning the drive that runs s the os and software to make it load samples as well? You're actually probably slowing it down. Partitioning doesn't physically split a disk up.

burgerproduction
To add my 2 cents:
I'd put the OS, programs, FXs and Samples on the SSD and have an external HDD linked via your SATA connector as the recording drive. The reason for this is that an SSD has a limited number of writes over its lifetime. Accessing samples doesn't require any writing (unless you bounce/freeze the track) so you SSD will last longer if you are only reading files. 
I record live instruments and the huge file sizes and multiple takes would exhaust the SSD more quickly. HDDs don't suffer from this as you can write/erase/write to them an infinite number of times without effect. The connection speed via SATA is more than fast enough to accomodate read/write speeds for the audio tracks, while the SSD will boost the performance of the programs and VSTs.
Hope this makes sense.

This is correct information. SSD drives have limited write rewrites so it is a very good idea to make the SSD drives read only to extend their life.
There  can be issues with interrupt times using PCIe SSDs for audio, creating glitches and greater buffers. In other words the huge bus capacity of the PCIe SSDs interrupts performance on your interface.
Samsung Evo brands have the best cloning software for name brand PCs (HP,DELL etc) The SATA drives are perfectly adequate unless you have an expensive PC.
The Pro versions are the best for write speeds and longevity is hardly a concern.
For PRo video use the NVMe SSDs are the best

So, I've been reading that you shouldn't record to (i.e.: 'write to') an SSD due to the limited amount of times you can write to them. Best to record to the companion HDD?

Billy86
So, I've been reading that you shouldn't record to (i.e.: 'write to') an SSD due to the limited amount of times you can write to them. Best to record to the companion HDD?

Look at the TBW (Total Bytes Written) specification for the SSD's you're considering.  It's an indication of the writing durability of the drives. You'll see values in the hundreds of terabytes.  Perhaps 5 years ago this was an SSD characteristic about which you should be concerned, but it's hardly an issue any longer.
 
Add up all the data you have created over the last decade or so to develop a proportionate understanding of how durable these newer SSD drives are expected to be. 

Kev999

Genghis
I recently did the upgrade myself to a Samsung 850 EVO, 1TB drive. It came with the software to clone my old hard drive, and it was a pretty easy, painless process.  After I did it I realized I was really only using about 300GB on the boot drive, so I partitioned it using a utility called EaseUS to a little over 400GB for  boot drive and the rest for samples.  I copied my Superior Drummer 3 libraries over to that partition so that it loads faster.

 
In your case, two smaller SSDs would have been better than one single large one.

Thanks for the info.  This bottleneck is really keeping me from getting any recording done.  I wish I would have known that before.

My computer's OS is installed on my SSD also. I also store my projects and library there for faster loading.