Apacer RAM is not meant to be anything special. With 8 Samsung CC4 32mb chips
per module and rated at the very high 3/7/4/4 timings at 200MHz while using
2.5v, it is meant for the OEM market, providing maximum stability. It is rather
cheap though and it has proven reliability.

 Dual Channel DDR SDRAM Roundup

That’s right, no 2/5/2/2 graph. The memory wouldn’t be stable
at any voltage setting with the timings set so tight, no matter the frequency.
It’s not something strange; many modules do not accept too high or too low
timings due to their design. For cheap memory, it does far better than expected
when the memory timings are set high. Concerning the little improvement that it
gives from high voltage settings, it did heat up a lot by that much voltage.
It’ll require good heatsinks on it else it might not live too long. It won’t
last for too long even with heatsinks on. Also, a little burn-in period might be
required for the modules to get used to high voltages.