Why is there no speed increase when using ZFS + SSD cache?

Question

ZFS

Good day.
I assembled a machine for proxmox for test tasks.
Well, for storing files.
5 HDD + 1 SSD / 16 RAM
Raised guest OS win7
Ran tests for writing / reading. Used Crystal Disk MArk
See attachments
Test for 1 GB ( without SDD cahe )

Test for 16 GB ( without SDD cahe )

Test for 1 GB ( + SDD cahe )

Test for 16 GB ( + SDD cahe )

SSD OCZ Vertex A
Added like this
zpool add -f rpool cache sds
After that, you can see that cache is being used.
# zpool iostat -v 1 The
question is - why is there no increase in speed?
Maybe I'm doing something wrong?

Answer 1

Measure at least a hundred gigs, otherwise your numbers are bullshit.