"Significantly" is subjective.
A Ryzen3 can pair well with much stronger GPUs than a 950, so that's the obvious place to start.
What PSU do you have?
What RAM do you have? What speed?
What resolution do you play at?
However, it's worth monitoring your utilization - CPU, GPU and RAM in whatever games you play. Chances are, with that hardware, something will be maxing out at 100% usage at least some of the time.
I'd suspect, after checking that, the GPU will still be the place to look. At ~250quid, you have options. 1660TI, RX580/590 etc...
For the money, I'd think a GPU upgrade, and RAM upgrade would be a solid way to go..... but I'd only go that route if the CPU is on your "to do" list.
PCPartPicker Part List
Memory: G.Skill Sniper X 16 GB (2 x 8 GB) DDR4-3000 Memory (£62.91 @ Amazon UK)
Video Card: XFX Radeon RX 580 8 GB GTS XXX ED Video Card (£159.00 @ Amazon UK)
Total: £221.91
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-07-29 23:19 BST+0100