PCIe wattage requirements, can it be downclocked?

[PCN00B]

I'm putting together a car PC, and using the online PSU calculator, I notice that using PCIe cards (Sound Card, WiFi, TV Tuner) in PCIe slots; x16,x8x4, requires quite a bit of wattage. When I would calculate it using a PCIe x4 slot compated to a x16 slot, the wattage is much less.

So my question to you guys is what can I do for components that can only be mounted using PCIe? Can the PCIe slot be downclocked to a x4 to conserve wattage? Is the online PSU calculator swayed toward high wattage because it is expecting someone to use a high wattage component?

 

[idkfa]

Im no PSU expert, others around here are. But if I had to guess I'd say you should list the exact components you want to use and what wattage you calculated.

And

 

[PCN00B]

Thank you.
I didn't think that components would be a critical part in knowing if the mobo could be down clocked, but here's as follows:
ASUS Rampage IV Gene LGA 2011 Intel X79
Intel i7-3770K
4 x 2G DDR3 RAM

Thats really it thus far.

 

[idkfa]

Maybe I got you wrong, but I think if you can tell us what wattage you calculated and what wattage you actually want to draw can answer the question if downclocking (I don't know if this is possible or not, but I doubt it) is necessary at all.
But yes those PSU calculators tend to mean too good, expecting a higher power draw than you'd actually encounter.

 

[PCN00B]

eXtreme Power Supply Calculator

By just calculating the default choices you get a base line of 88W. By just adding one PCIe x16, the wattage requirement jumps to 156W, a 78W increase.
By just adding a PCIe x1 it only increases 14W.