I am a little bit disappointed that I can't alter voltages but in the end, the missing power connector and the overall performance make this card a keeper.
Not need to be disappointed yet, as future versions of RBE, MSI afterburner or other tools may also support the VR chip of your card on 5750s.
Edit: What really puzzles me is the power reduction that would have been possible with further voltage tweaking. I mean with such an effective vr circuit it should have been possible to get this card under 10W idle and probably even under 55W load (with a good sample)!
I'm a HW engineer, no gambler and no used car salesman, so I neither want to bet with you, nor convince you. Just my 2Cents: imho the card is really only about voltage reduction, and maybe better/more stable vr. So I wouldn't expect it too be anymore efficient than the plain vanilla reference design vr.
Honestly I'm very pleased with the power consumption values from techPowerUp, and really don't expect to get them some down much further, unfortunately especially not the idle values.
Why? Well to get the load wattage down, first lower the voltage. But the most efficient way to get the idle values down is not only to get the voltage and clock further down (btw. clk is already down to 157MHz so there is not much more to go).
If you look at all the idle results in reviews, you'll notice that comparing similar cards, not always the cards with the lowest idle voltage will have the lowest consumption.
But you need more for low idle wattage than just a low GPU idle voltage, e.g. you need a good VR efficiency at low wattage and that often means a worse efficiency at high loads.
Then there is is the RAM.
Usually the idle RAM voltage is the same as in load. So with 1GB highspeed RAM you need already a lot of juice for that. I remember seeing reviews showing that the difference between 512MB and 1GB GFX cards might be as small as 2-3W typ., but that was much slower RAM and also means in idle you still have easily more than 5W just for the 1GB RAM. Then there is the memory controller inside the GPU, which is seperately powered by the RAM voltage and clk, so no saving there in idle. But I thinks it's getting to technical again
Just wanted to point to, that there is probably quite a high minimal wattage you'll never get below with a 5750, even with further voltage tweaking ...