Guys please stop complaining. First of all this is a competition and you have until the end of the month to get your entry in so don't stress out. You do not need to find it today or tomorrow as there is plenty of time left so calm down a little.
My tips are forget about the clues so far as they aren't cryptic or misleading.
As a recap of the clues so far. The first clue was "Eagle eyes" That was referring to Tom's signature which has now changed so don't worry about that one. What it was referring to was that the image is on the main website somewhere. This means it is somewhere under
www.overclock3d.net and it didn't include the forums, facebook, youtube or the competition page. It dosen't include the original image or the version in the printable version.
The next clue was turn off ad block or any other add blocking software in your browser for the site as it will stop the image popping up. Do not worry about millions of ads as the ads aren't that big or intrusive and it helps the site so be nice and turn them off for this site. If you can see the ads to the right hand side and to the top of articles then you know they are off.
My tips would include have patience. Take your time as you have over 3 weeks left to find it. Do not worry about repeating articles as everyone has them and they pop up in different pages but they won't stop you seeing it.
Next bit of advice is use your spare time. Do not make this competition a priority but rather do a little bit of searching in between jobs or tv programs or while having something to eat. That way you wont get burnt out or frustrated by the whole thing.
Next use some logic, I cant say why or how but use some logic when searching. One bit of advice I can give you though is if you literally search one section of the website and its not there then search another section instead of saying I must have missed it. It is there.
Use the brute force method and have some patience and you will find it, you cannot miss it when you open the right page trust me its big and right in your face.
As for people saying its not fair well I would have been of the same impression about treasure hunts on other websites that are usually a first come first served policy so you have time against you there and I hate those as its more pot luck in finding it. Here at least you have a better chance of finding it and then you have a draw so it is fair if you put the work in. At the end of the day its a free graphics card worth 600gbp so stop complaining, you sound like its your right to have a chance to enter.
Go forth now and look and remember to take breaks.