Judge my computer (performance question)

My game is running well on new computers with a graphics card.
But it barely runs over 30fps on Medium/Low quality on my old desktop.

The question is, how decent or bad is this computer in 2018? Is 30fps at 'low' quality demonstrate that I've optimized or that I have to do more?

I know this is a subjective question, but this machine does have a dedicated graphics card, so it's technically an old game machine.

AMD Athlon II X4 640 2.8 ghz
4GB RAM
AMD Radeon HD 5700, PCI x16, 1GB Vram
SSD (newest part, only a couple of years old)

 

Play some steam games similar to yours. Get a feel for it, it's your research for your particular game type.

 

You're unlikely to encounter too many computers with this hardware. What few individuals I've known who have a habit of sitting on an older gaming rig almost never go beyond six or seven years between new systems and this one is at least nine years old.

That being said the graphics card is still superior to even the best Intel HD GPUs.

https://www.futuremark.com/hardware/gpu/Intel+HD+Graphics+630/review
https://www.futuremark.com/hardware/gpu/ATI+Radeon+HD+5750/review

 

A 9 year old mid grade for its time graphics card, on a 7 year old CPU, with a below normal amount of RAM. If the game is playable on this hardware at the lowest graphics settings I'd consider it a success.

I think you're totally fine making the assumption that players of your game will have newer hardware than this.

 

You all gave very clear feedback. Thank you.