Special converter for 1000W of power?

I know that Japanese power outlets have a lower voltage output. Will I need a special converter for a power supply requiring 1000 watts? Will it cause any problems to my computer?

-Davis

If your computer requires 1000watts then that means it will draw roughly 10 amps in Japan (vs. around 8-9 amps if used in the US, or around 4.5 amps if used in Europe). That is within the limits of a typical house circuit in Japan (here its 30amps for example). Just don't overload the circuit that the computer is on to avoid tripping the breaker (cutting off power to your computer, and possibly damaging it).

And for the power supply, do I need a converter?

Davaul,

And for the power supply, do I need a converter?

Without knowing the voltage rating of your computer, it is kind of hard to say. The Japanese mains voltage is 100 V, so if your computer says "100 - 240 V", you're fine. If not, you may need a transformer.