So i just bought a used EVGA 980 Ti SC+ ACX+
The backplate has the sticker that says 06G-P4-4995, but that doesn't mean that the card is a SC+ ACX+ I mean the backplate can come from another card.
So is there any other way to see which card it is? I can see two other stickers with C/N and bios version, but i can't find anything when i google them

By backplate ,do you mean the circuit board sticker? I know yours comes with a backplate installed. The sticker should be correct, but you can double check by running GPU-z, then hit look up on the main window, it should show correct info. It will also show a lot of other useful info,  current BIOS,ect. Hope that helps.
 
https://www.techpowerup.com/downloads/SysInfo/GPU-Z/

Notfordman has the right idea. Verify clocks/vbios version with gpu-z. I would also call evga and ask them to verify the serial number.

Well my first EVGA 980 Ti SC+ ACX+ has i custom bios at 1500/4000
Here's some prints from GPU-Z
 
My first 980 Ti

 
The second one and bought used

 
Except the clock speed, the Pixel Fillrate and Texture Fillrate differs. Also Memory type seems to be off? Did not know Hynix made memory for the 980 Ti?

Looks like a legit 4995. A 980 ti could come with hynix memory.

Thanks mate.
So what does Pixel Fillrate and Texture Fillrate means and why do they differs? Is it becouse the higher clock speed on the first card?
And is there any drawback with Samsung vs Hynix memory? Can't recall i've read anything about Hynix

Lookup pixel fillrate and texture fillrate on google. Yes, higher clocks will change the fillrates. People say hynix overclock less than samsung memory.

my 980 ti has Samsung but looking at the bios info like at techpowerup   I guess it can have  Hynix Samsung or even  elpeida    then if you register the card with evga  if not legit  would the registration be rejected  or void ?? 
 
[for a example]
Memory Support
  GDDR5, Hynix
  GDDR5, Elpida
  GDDR5, Samsung
 
https://www.techpowerup.com/vgabios/172890/evga-gtx980ti-6144-150527
 
then I guess with any luck of the draw can come into play with any ocing you try to do ?    elpida memory is the only one in my opinion  that if I got that would of hurt my feelings 
 
 
is strange the one default clocks is lower  and being the same cards  I'd think that should be the same and equal  evga spec of that card  number  but does match to techpowerup  on that at a 1102mhz ?
 
I see now the bios is not the same revision  or been flash  before hand  or your mod was not the same for the 2 ??
 
https://www.techpowerup.com/vgabios/?architecture=NVIDIA&manufacturer=EVGA&model=&interface=&memType=&memSize=&did=10de-17c8--&since=

Yeah you right. I've never even heard about Elpida but it seems as Samsung is the most usual one.
To clarify. The first screenshot is from my old 980 ti that i've had for a year or so. I've changed the bios with a custom one that i created my self. Just noticed that EVGA 980 Ti SC+ ACX+ comes with two different default clock speed, both 1102 and 1190 http://eu.evga.com/Products/Product.aspx?pn=06G-P4-4995-KR
 
Well i flashed the same bios from the old card to the "new" card and it seems to work just great, but since i have to wait 1 more week for the waterblock i can't push it 100% :) I hav eto wait and see how the new clock speed works.
 
And yeah, sorry for my lack of English :D

minlillaponny
Yeah you right. I've never even heard about Elpida but it seems as Samsung is the most usual one.
To clarify. The first screenshot is from my old 980 ti that i've had for a year or so. I've changed the bios with a custom one that i created my self. Just noticed that EVGA 980 Ti SC+ ACX+ comes with two different default clock speed, both 1102 and 1190 http://eu.evga.com/Products/Product.aspx?pn=06G-P4-4995-KR
 
Well i flashed the same bios from the old card to the "new" card and it seems to work just great, but since i have to wait 1 more week for the waterblock i can't push it 100% :) I hav eto wait and see how the new clock speed works.
 
And yeah, sorry for my lack of English :D

There's not two different clock speeds. All stock SC models are base clock at 1102mhz and boost clock at 1190mhz. It's because you've modified the BIOS that you have different clock readings.