Question is this Gptron gtx 750ti 4GB GDDR5 legit good or not?

Probably fake, and really something like a GT520/610/620 or 430/530/630 given the low-profile and lack of a power connector. The big clue is the inclusion of two analog outs--the last nVidia cards that commonly came so equipped were Fermi, and most of those could not even actually drive two VGA monitors at the same time.

The Kepler and Maxwell cards which came with a VGA port only had DVI-D ports, while those without a VGA port could have one DVI-I accompanied by one or two DVI-D (whereas Fermi could have two DVI-I, or a DVI-I plus a VGA like this card). That's why the Kepler version of the GT630 had DVI-D while the Fermi variant had a DVI-I alongside the VGA and HDMI (you can tell them apart when googling pictures of them because the Kepler version is also only PCIe x8).

So unless it's a super-custom 750Ti, it's fake. You'd think though if they went to the trouble of custom-making a very special 750Ti (750Ti were available in rare single-slot or low-profile versions but never both due to the 60w TDP), that they'd proudly trumpet that and the extra external TDMS PHY, but they haven't. Instead they were so embarrassed that they didn't even brand the card with their company name, only "nVidia."
 

Exploding PSU

Honorable
Jul 17, 2018
477
154
10,870

Small world. Hear it from someone who have shopped at that exact store :

I know that seller (GASOL). He's quite reliable. I bought my current CPU cooler (Cryorig H7) and a completely unbranded RX 470 (turns out to be a "digital alliance" product) from the guy. Both purchases were legit parts. He's got a knack for sourcing weird, rare, and esoteric parts.

Here's the thing though, I try to stay away from weirdly branded parts, especially GPU. There's just too many GTX 5xx series cards being branded as anything from GTX 750 to 1050 out there. Trust me, I've been there, and it wasn't pretty.
Sure, there is a small chance that the 750 Ti is indeed 4GB, those people at Chinese "engineering sweatshops" could frankenstein almost anything when they're at it, but I won't take the risk. I'd look away and find something else, there are plenty of other choices in that price range. You can snatch a used name-brand GTX 970 for around that price, and that's a lot better than this.... thing.

If you're limited by your PSU but you still need the 4GB VRAM, a bit of looking around could net you a used Gigabyte 1050Ti with 4GB VRAM, and that's better too.

That product reminds me of those chinese X79 motherboard whose chipset was sourced from harvested server motherboards or something. Those were the days.