Gtx 950 - 75W version vs 90W (need explanation)

[The Protagonist]

I guess most of you already know there are some 75W gtx950 versions from Asus and MSI instead of default 90W, which doesn't require additional PCIe power. Sounds power efficient and worth some extra € to pay.
The question is - do they perform the same as 90w versions? Why then they have the same body with same heatsink and even two fans for cooling? May it throttle on heavy loads or smth?
Thanks in advance

 

[Robert Cook]

I dealt with a little evga card that ran on PCIE slot power only. obviously you could not overclock that much as there was no voltage control, but that card out of the box is already faster than many 950 cards. heat wise they tend to run cooler as the chip is a less power hungry chip. if you do not want to OC then get one, they are nice cards.

 

[Trenchcoat]

The 90w cards run mainly off the six pin connector to the psu thus imposing next to no stress on the motherboard. They can therefore be overclocked easily enough to match a stock 960 in performance.

75w is the maximum recommended you can safely draw from a single motherboard GFX slot. I've seen tests of these '75w' cards drawing even more power. If you're confident with your motherboard manufacturer and you don't want a little headroom;go for it.

 

[The Protagonist]

I'd rather overclock my fx6300 from 4Ghz to some more. Never felt I need to overclock my MSI660OC (which is already sold, so I'm looking for a replacement), so yeah, I wont overclock a new gpu either way. I guess Nvidia rushed the release of their 950, and managed to take much more efficiency from these chips after a while, huh?
Still - why this one (https://www.asus.com/Graphics-Cards/GTX950-2G/) needs to be so well cooled, while another one (https://www.asus.com/Graphics-Cards/MINI-GTX950-2G/) is smaller and has only 1 fan? Didn't find any difference in spec. list. Did I miss something?
P.S. my MB is Asus M5A78L-M/USB3 with additional copper VRM heatsinks.

 

[Robert Cook]

well part of it is looks. the dual fan one is supposed to look higher performance. Also depending on whether they are binning the chips in those cards, the small cards might actually have chips that put out less heat. or the fan just spins faster to compensate. also the smaller card might run a few degrees C warmer at full load, but in a tight case, the other card simply would not fit. You raise good questions though, it seems many things on GPUs are frivolous and hard to understand.