I have the same processor running on an ASUS A8V-E Deluxe (VIA K8T890) and have the chip stable overclocked to 2.8Ghz (255x11). To get there, you need to up the Vcore past 1.6v. Mine is at 1.63v (setting the Vcore to the max 1.5625v setting and also setting the CPU Vcore Offset to +200mv). Not sure your board can do the same thing, but at just the 1.5625v setting, you can get a stable overclock of 2.7Ghz (252x11). I run the memory at 333, which keeps the memory at stock speeds. (255x11=2805; 2805/14=200 or DDR400). The stock speed allows my memory to run at very low timings of 2-2-2-7. (I use two 512MB sticks of low latency Corsair XMS).
Upping the Vcore increases heat, so I use a Thermalright XP-120 heatsink with a Panaflo 120mm fan. With a stock unit, you should be fine as long as you keep the Vcore around 1.5-ish and have good airflow in your case. You should be able to hit 2.7Ghz with ease using the 333 memory divider; lower than 2.8Ghz will mean that your memory will be running lower than DDR400, but not all that much lower.
Having this thing clocked at 2.8Ghz makes it into a nice budget FX-57. How sweet is that?