Hi, even though a have a lot of experience building and repairing computers I never overclocked before, I build a PC for a friend and I build a Core 2 Duo E4300 with an ASUS MOBO:
http://www.newegg.com/Product/Produc...82E16813131041

I Overclock it using the ASUS Bios, I know Core 2 Duo are very reliable for overclocking, but I don't know how safe it is, I just overclock by 10% to reach 1.98Ghz, and temps don't seem to raise too much.
I believe she will be ok, but I'm wondering how can I know how far can a CPU be overclocked, ASUS Bios tops on 30%. I just want to hear some opinions about this, Sandra Benchmarks seems to improve a lot when I did the overclocking.

BTW I put this RAM on it:
http://www.newegg.com/Product/Produc...82E16820145527
She don't game at all, she only need a fast computer for accounting at home and some other basic stuff.

Thank you all beforehand for your input.

Well, if she doesn't game at all, I think you don't need to OC the CPU. The 4300 is pretty fast even at stock speeds. Heck, I have underclocked my CPU to 1500 Mhz and 1.31 volts, and it's still pretty fast (even for games).

But if you still want to OC it, 2.0 Ghz would be a great speed. These chips can reach 2.6-2.8 Ghz easily, but it would be a waste of time if she doesn't run games @ all.

Just my $0.02

so 2.6, 2.8ghz... great!! that's over 50%, and.. I know... I really want to give her my P4 and keep the Core 2 Duo, :P but she wouldn't agree to that, she said she want entry level of the high-end/fastest computer available, so I suggest the 4300 and she's happy with it, but I keep thinking it's a waste of such a great CPU, for the use she gives to that computer even Celeron 2.8 would be a great option, but Now that I've tried the Core 2 Duo (even the 4300) I really wanna build one for myself, and finally move on to PCI-E. Thanks for your comment!

You're welcome, and believe me, even my underclocked Core 2 Duo processor is insanely fast

Looks like you need to update your signature to reflect your newly underclocked CPU :P... and WHY is it underclocked? You say you game with it, so why not get every last bit of performance out of it?

why the hell would anybody underclock their cpu

My overclocks are like 2mhz, Last time I accedently overclocked my GPU by 3ghz ( It was reading MHZ and I forgot how much MHz was in 1GHz ) and it literally caught on fire

I have underclocked my CPU because it is running too hot. With the underclock, now it never gets to 50°C

But I will overclock it when I get my new cooler
And yes MetalX, I have to update my sig...

I am going to overclock mines as not to strain the motherboard, see check this out.
The RAM is DDR2-800, but the motherboard uses 667
However, the board has an FSB of 1066, which is perfect for Core 2 Duo I have (1.8Ghz), so I was like. :P

Thus, I ended up underclocking the motherboards BUS to link well with the RAM.