[SOLVED] Is 2x molex or 2x Sata to 6-pin pciE-adapter a short-time option, or is too risky with a GTX 780 on a 450 W PSU?

[AJNameS]

Hello, so, said in short, I wonder if I can temporarily use GTX 780 with a Corsair CX 450 (Gray, CWT) with an adapter like the ones I mention in the title? My main concern is the safety and not to melt anything around. I have only one 6+2-pin cable while the GPU wants also one 6-pin connecter, but I wonder if I can bypass this issue with an adapter.

The brands & models of the two GPUs, that I might 'test' are:

• Palit GTX 780 JetStream;
• Gainward GTX 780 Phantom, possibly this is a GLH one, but the previous gpu is more important;

Both are factory-overclocked [6%, or if the 2nd one is a GLH, then up to 14%, which I guess may go up to 265-285 W (correct?)]

And my main concern is the part of wattage, that will press the adapter and the PSU with its molex/Sata cables:
Aren't 75 Watts actually covered by the motherboard's pciE slot? If it works this way with these GPUs, then this means that actually the connectors are pressured by а total of 190-210 W. Or this 75W-thing only if my GPU doesn't use additional connectors?
Are the PSU Molex & Sata cables made to resist up to 60W or it is 54? Or else? (yes, I mean cables, not just 2 connectors on one cable)
Is the 2x molex to 6-pin a worse idea than the 2xsata to 6-pin? Or it's the other way back? Or the same?
Is the 6-pin adapter actually going to be a bit less pressured? Like this - the 8-pin one, that my PSU already has, e.g. to cover 108-120 Watts, while the remaining 82-102 W to go to the adapter, and 41-51 per molex/Sata cable of my PSU respectively?

The total wattage is not that much of a concern to me, though I'd go something close to my max of 450 W.
Anyway, the other components of the probable test-system are:
motherboard - microAtx, Asrock B85M Pro4;
cpu - i5-4690, non-k - I may temporarily disable Intel turbo boost and downclock a little if I happen to test a Gainward Phantom GLX version;
ram - initially 2x4 GB ddr3 1600 MHz, I'd temporarily remove the other 2x4 GB
Standard mouse & keyboard
Fans on the motherboard - 2x120 mm, the first one running at 50% (cpu fan), the 2nd at 100% (case fan)
one usb 2.0 cable with USB Tethering running
low-end headphones
other separate components around 'd be ran with another PSU (this dual-PSU 'trick' is tested already) - SSD 240 GB, probably also these: DVD-RW Sata 1, HDD 1 TB & 7,2k rpm, 1-2 molex fans.
Which means 160-170 W from the other things if they get to 100% usage, thus meaning 280-290 W are free for the GPU. (correct?)

I have places where to buy mid/high quality adapters;
I plan to initially undervolt the GPU and run it in 50%, 60, 70, ...100%...up to its 106-114% of the 250 W in these overclocked ones. I guess MSI afterburner and probably Linux can be effective enough here, as I don't want to play with the GPU bios.
Usage distribution: 4 hours intensive per day (games & benchmarks running with MSI Afterburner around), 12 hours idle/low usage, 8 hours turned off, this for up to a week.
I'd point 1-2 fans to the adapters while touching them from time-to-time if them cables heat much.

There are also other GPUs that I might test with most of them being covered by my PSU, and while having excluded a GTX 690 due to too big wattage there, I wondered about these OC 780 gpus. I have my own GPU, but I want to check these out for some time.
What do you think? Would there be fireworks for sure, or a temporary setup like this would survive? Correct me if I am wrong in some things I write.

 

[kanewolf]

There is never a safe approach to using cheaters like this. Your power supply is not designed to support the graphics card.