Sapphire HD 2600 XT Power supply query

[kelsin]

Today I purchased an ATI Sapphire HD2600XT 256MD GDDR4 card

My current card is Geforce 6150se and I can't even run WOW properly on it at full res which for my 22" monitor is 1680*1050

I bought the new card today but before I put it in my machine I read the required specs which state I must have a PSU of 550W or better

On opening my machine I discovered I have a Bestec 300W(Maximum) PSU

Is there any point whatsoever of me taking the card out of the box and putting it in my machine or do I just take it back?

I've probably answered my own question but thought best to first seek advice of experts

All feedback greatly appreciated

MOD EDIT: Crossposted - Zap

 

[Auric]

Shouldn't be a problem. The 2600XT's peak draw is about 4.1A and a quick goggle reveals the PSU may sport dual +12V outputs of 18A each. Try to confirm that by checking the label and then it's all systems go