How to increase the performance of a gigabit network of 7 computers (+server)?

Question

RAID

There is a gigabit network from 7 computers (win10). windows server 2008 r2. Hard disks on the server 7200 rpm. There are no raids. connected to the server via a Cisco SG100-16 v2 switch.
All computers have gigabit network cards.
The task is to increase productivity by reasonably minimal means (100-250 thousand) (recording and reading data over the network).
To be clear, our company is engaged in 3d graphics. Frequent access to the same files and large amounts of transmitted, recorded information. The usual network speed is 80-100 MB / sec (when 1-2 computers are working). When all computers are accessed at the same time, performance drops dramatically. (up to 5-20mb/s)
Questions:
1. Will the installation of a 10 gigabit card on the server solve the problem (partially or completely)?
2. Will it solve the problem
3. Is it possible to switch to a 10Gb network with a budget of 250 thousand? And what is needed for this, if possible.
4. Which Raid technology is best for this network? what hard drives are best to use?
5. Are there any other options?
PS I understand networks very superficially. If any information is missing, I will add it in the comments.
Thank you.

Answer 1

1) 100 Mb / s - adapter performance of 1 Gbps. Accordingly, this performance is divided among all participants. Yes, installing a 10Gb card in the server will help you. In this case, the switch itself must have at least one 10Gb port. But you will bump into disk performance.
2) disks, install - SSD, or make raid10 from ordinary disks. Raid 10 can be made using Windows, it is advisable to buy an adapter for this business, but it's better to just buy SSD drives.
3) you do not need a full transition to 10Gb, it is enough that the server and switch have 10Gb ports.
4) see item 2.
5) you can stumble upon the performance of the server, it is desirable to have a processor with several threads on it, preferably some kind of e5-2620 cheon.
PS. In terms of equipment (wow, how prices have flown in !!), the cheapest is a netgear GS728TX-100NES switch and a dlink DXE-810T or intel X540-T1 card.
This is what I vouch for, it works! We ourselves mainly use the Dlink DGS 3420 and 3620 series of switches. We do 10Gb by optics.
Actually the price of the issue is ~ 15000 card (dlink) + ~ 38000 switch (netgear).