Which is better (timing or speed)

[Ibasaka]

I'm still a bit new to overclocking ram, so I have a couple questions.

I'm using a set of Mushikin DDR2 2Gb (2x1gb) @ 800mhz (stock).
heres some of my questions.

Why do you need to raise the timings when raising the dram frequency?
My stock settings were 4-5-4-11 @ 800mhz, but I read a review on this set of ram and the reviewer said a good setting for this was 5-5-5-15 @ 950mhz. But I'm wondering whats the difference about the speed and timing. Wouldn't it be slightly slower because of the higher timings?

 

[Asian PingPong]

Why do you need to raise the timings when raising the dram frequency?
My stock settings were 4-5-4-11 @ 800mhz, but I read a review on this set of ram and the reviewer said a good setting for this was 5-5-5-15 @ 950mhz. But I'm wondering whats the difference about the speed and timing. Wouldn't it be slightly slower because of the higher timings?

To answer your first question, timings are measured in clock cycles, so the more clock cycles per second, the less time between clocks, the faster the ram must retrieve data. There is a physical limit on the speed the chips can return data, so in order to not pass that limit, higher speed requires higher latencies.