Upgrading The CPU On A Factory OC'd Mobo...

I'm currently running an Asrock 2core1333-2.66 mobo which was bundled with a Pentium Dual Core e2140 cpu factory oc'd from 1.66 to 2.66ghz. I use an Arctic Cooling Freezer 7 Pro to keep temps nice 'n low. Mem consists of 2x1gb sticks of PNY PC2-6400 (400mhz) ram. Graphics are supplied by aSapphire HD4850 512mb PCIe graphics card. Its all powered with a decent single rail 550w power supply.

I've just purchased a Core2Duo e6850 and i've heard that this cpu can be taken up to 4ghz from its default 3ghz safely on air cooling (with a good quality cooler of course). Will I be able to drop the e6850 straight into the motherboard using the existing bios settings to achieve a safe OC, or would it be better to err on the side of safety and reset the bios to default settings. Even on default settings I should see a significant performance advantage over the Pentium Dual Core.

 

Thanks for the sound advice Triple6. I'm a little new to this overclocking milarchy, but I suspected that might be the case. Much of this build is getting a bit long in the tooth now and the e6850 is a stop gap until I have the funds to build a decent, budget quad core sytem. Ah well, even running at stock I should see a nice speed increase over my old CPU.

One more question if you have time: Sapphires minimum reccomended power rating for my graphics card is 450w. At the time 550w seemed to offer decent headroom. Will that be compromised by the increased power consumption of the e6850?