I have a HP xw6600 xeon E5405 2.0 ghz system, I was browsing ebay for a second cpu and I stumbleg upon 2 E5462 cpu engineering samples(not sure if they come with cooling or even are fully compatible with my 5400 chipset), the question is: is it worth the 450usd to go there or should i just buy a E5405 as to not waste a cpu? Note: I'm a home user, no fancy programmes, the occasional gaming and Photoshop/Corel Draw kinda guy. Thanks for your patience.