If you Google the number on the chip it'll let you know what exact GPU it is. But from the other markings on it it's a standard fx5700

Sadly a Google search didn't reveal anything useful, except for a Go5700-V and this is most certainly not a mobile card.
I think, at this point, it's pretty safe to say, that this is indeed a FX 5700.
This weekend, i'm planning on installing Windows 98 SE and hopefully making some benchmarks and also playing some games.
I'm happy, that we're managed to find out, what this card is. Thank you for encouraging me to buy this card.
Buying it was definitely not a waste of money.
I also want to say thank you, to everyone who was involved in this thread. I really appreciate it.
I'm really satisfied with the end results.

Good I'm glad it's all worked out for you. I'm very much looking forward to seeing the benchmark results.

Wilius wrote on 2020-11-12, 09:46:

What should the specs of a 256MB FX 5700 normally look like?
What causes GPU-Z to display a memory bandwidth of 16.0 GB/s?
Is this a software or hardware related issue?

Looks like this is the usual spec. 5700 256 MB of Abit, Asus , Inno3d and Sparkle also used 250 MHz, Gainward, MSI and Leadtek opted for 275.

There is no software working reliably with old cards. That's the lesson I got with 90's cards. Still, it is a bit shocking to see GPU-Z failing with something so "modern" as FX generation.

Well, I have to say, that I'm using a very early version of GPU-Z.
GPU-Z v2.35.0 refused to work on my system.
Is this version even still supported on XP?
What is the latest version of GPU-Z, that you're aware of is still working on XP?

I would say GPU-Z 0.8.2 will be perfect.

Thanks!
I'm looking forward, to try this version soon!

I've now finished the installation of Windows 98 SE.
I also installed most of the Software, that I need to get this thing running.
However, not everything went smooth.
For some reason all of the benchmark software, I tried to install, got corrupted.
I'm going to reinstall them ASAP.
I hope, i'm soon able to share the benchmark results with you.
Till then, I beg for a bit more patience please.

Finally, here are the benchmark results.
That took way longer, then expected. I'm sorry about that.
For the first benchmarks, I used 3DMark99 Max, 3DMark2000 and 3DMark2001 SE.
In 3DMark99 Max, it scored 7583 3D Marks
In 3DMark2000, it scored 14467 3D Marks
In 3DMark2001 SE, it scored 11058 3D Marks
I'm looking into doing some more Benchmarks in XP too.