Like a Tom's Hardware, Anandtech and a few dozen other sites? Sounds like a cool idea, but just know it's going to be a uphill battle until your well established. There are a lot of reputable sites out there right now such as the ones I've listed above that will be pretty hard to beat. If your up for the challenge though, be trustworthy, comprehensive and do something those sites don't.
Also, it's expensive to get one of these sites off the ground. You need to get some popularity before companies like ATI and Sapphire start sending you their parts for free in order to promote them because they know your site get's a lot of traffic. Until then, you'll have to be buying your own hardware to test.
Good luck though! There's just a lot to consider you know? But to summarize what I said above. Offer something unique that those other sites don't, and be trustworthy and comprehensive.
"If I have seen a little further it is by standing on the shoulders of Giants" - Isaac Newton
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