Hey I want to know why 2000 MaH's suck so much lol. I have 20 rechargeable AA for my GP2X, 12 Rayovac 2000 mah, 4 Duracell 2100, and 4 Rayovac 2500's. On the 2000 and 2100 Mah's I get like 30min to 1 hour, but on the 2500's I get like 4-6 Hours. OMG, that 500 extra MaH makes all the difference, I just would like to know why?

Because the voltage on the lower-capacity bateries falls off faster as they're drained. I think it's inverse exponential something-or-other.

Yes, the GP2x drains batteries quickly. 4-6 hours - I don't get that on my batteries and I use 2500NiMH, 2650NiMH and 2700NiMH ones.

I guess the 2000 batteries are pretty old already.
I don't think that have that much capacity.
They break down after 1 - 2 years.

It could be the inverse square law.....or it could be that they are wearing out!

I have a pair of branded 1900 ones. They're lasting more than 2 hours.
With 2800 I had more than 4hours but after a while they ceased to work properly (30mn too).

We'll thanks, I still don't know why lol. But the 2000 Mah batteries are new, and I get 4-6 hours depending on what I'm playing clockspeed, but I never get less than 4 hours on 2500Mah's.