What happens when the wattage of the PSU is low?

[Kc779]

what happens when the PSU wattage is lower than the recommended wattage of the video card? will it be slower?

 

[Supahos]

If it's a really good power supply and it's a small amount, usually nothing. If it even an average unit it'll start throwing either not enough voltage to the computer or "dirty" voltage. Either if which can result in any and all parts dying. If you're doing this or consider this, stop and buy one that makes sense or a less power hungry GPU.

 

[Sakkura]

The official recommended wattages are exaggerated to account for systems with power-hungry CPUs etc. and to leave some margin for error for lower quality PSUs that can't quite deliver what they promise.

If you do end up overloading a good quality PSU, it will simply shut off to avoid problems from out of spec voltages or ripple (dirty power). Lower quality PSUs often lack that protection circuitry.