Why does is show my mem clock at 894MHZ, when i have OC'D it a little - in line with my core and shader clocks - 575MHZ, and 1329MHZ?

The shader clock is supposely 1600MHZ out the box?

Riva Tuner shows the same 894MHZ too.

that is correct mate..if y read in rivatuner 894 then y need to multiply it by 2..because it id ddr so if y devide 1600 by 2 you get 800..so if you run at 894 its 1788mhz.mine rivetuner say's 1008 so my mem runs at 2016mhz..so dont wurry and happy overclocking mate

[quotemsg=1834101,2,292213]that is correct mate..if y read in rivatuner 894 then y need to multiply it by 2..because it id ddr so if y devide 1600 by 2 you get 800..so if you run at 894 its 1788mhz.mine rivatuner say's 1008 so my mem runs at 2016mhz..so dont wurry and happy overclocking mate

DDR stands for Double Data Rate.
As ferdy says you need to double it fro the effective speed.
The marketing guys use the doubled figure as its bigger and sounds more impressive, while overclocking apps read the real clock speed.
Mactronix

Thanks guys, i did wonder if i should just double the 894MHZ.

Time to see how far it will go!