Microsoft storage pool question

[Samus21]

I have 4 18tb drives set up in single parity in storage pool with data on them already. The write speed is pretty bad. I’ve been reading there is a way to change the cluster size without reformatting. I didn’t know if there was a free program like minitool partition wizard. I also found a website that talked about resized the virtual disk. I was wondering if someone could help break it down for me and if it would erase my data .

 

here is the website

 

https://storagespaceswarstories.com/storage-spaces-and-slow-parity-performance/

[tkitch]

what is "pretty bad" write speeds?  And where is the data coming from?

 

Remember these aren't SSDs, so their performance is pretty bad in comparison

[Samus21]

So if I’m not using primocache I get a write speed of 0-25mb. If I use primo cache I get 50-170mb but it is constantly spiking and falling. I originally had 2 18tb drives in raid 1 but I added two more so I wanted to use storage space so I can continually add to it. I’d like to have a better write speed like I had in raid 1. So I wanted to know if I can use powershell to resize my virtual disk and create a virtual disk that has a better cluster size to increase write speed. I know minitool partition wizard allows you to resize while keeping your data but I didn’t want to spend the money on that if I could do with with power shell.   
 

the data is coming from hdd 6tb and moving to the storage pool.