Differences between "reference" non-OC NVIDIA GTX 780?

[Gremo]

My question is really about the "reference" GTX 780 cards (i.e. Inno3D N780-1DDN-L5HS, Zotac ZT-70201-10P, and so on...) with the stock titan-like cooler. These cards have a core clock of 863/900 MHz and memory clock of 6008 MHz.

Will I'll be able to overclock these cards like custom GTX 780 (assuming that the quality of the silicon is good enough)? What I'am asking is if they are locked to fixed CPU/memory frequency or voltages. For example I may buy the Inno3D GTX 780 3GB N780-1DDN-L5HS (core 863/900 MHz) and be still able to overclock it at 902/941 Mhz, like the model Inno3D GTX 780 3GB OC N78V-1SDN-L5HSX. Is this right? Is the PBC/Bios the same for all reference boards?

I would go for AMD R9 290, but not with the actual cooler/noise/heat. Even waiting for custom coolers (maybe it takes months), AMD lacks the DVI-I output and I'd like to connect my old LCD TV to my rig (unfortunatel TV's HDMI input has something wrong and picture quality is worst).

What you'll do? Wait XXX months and buy R9 290, saving some money? My rig (if matters):

i7-4770K (still stock)
Asus Gryphon Z87
16GB Crucial BallistiX DDR3-1600 9-9-9-24
Samsung SSD Pro 128Gb x 2 RAID0

Sorry for my english not being so good

 

[ViRGE]

They're no more locked than any other 780 card. The voltages are restricted to 1.2v or so, but the available clockspeed range should easily exceed what the GPU is capable of.

 

[Gremo]

They're no more locked than any other 780 card. The voltages are restricted to 1.2v or so, but the available clockspeed range should easily exceed what the GPU is capable of.

Then one should go for the cheapest... right? How about he PBC bios differences between reference cards, I.e. Inno vs Zotac?

 

[ViRGE]

Then one should go for the cheapest... right?

It depends on what you want to do. Obviously they're going to have different coolers, etc.

How about he PBC bios differences between reference cards, I.e. Inno vs Zotac?

If they are reference cards, then the PCBs are identical.