i have now 1 ssd Synology 400 GB (3400) in my nas for read.
Does is have sense to change it for 2 pieces of 1 or 2 TB WD red SSD's?
So for read and write.
My internal memory is orginal 8 MB Synology memory
Upgrading to two 1 or 2TB WD Red SSDs in your Synology NAS would provide higher capacity for storage and potentially faster read and write speeds compared to a single 400GB SSD. However, the actual performance increase will depend on various factors such as the type of RAID configuration you use, the type of workload you have, and the specific models of the SSDs.
Additionally, it's important to consider if the cost of the upgrade justifies the benefits you will get from it. You should weigh the cost of purchasing two new SSDs against the cost of continuing to use the existing 400GB SSD and potentially adding more hard drives for storage capacity.
Regarding the internal memory, 8GB is usually sufficient for most basic tasks. If you are running more demanding applications or virtual machines, you may want to consider upgrading the RAM to increase performance.