So i am looking at replacing my 9800GX2 with a GTX480 (possibly with a second one in future) and i cannot seem to find details on the different blocks available forthe GTX480. Ideally i would want to get a Nickel block with a plexi top. For one it looks better, and i also like to see inside the block so i can make sure there are not bubble cavities forming due to un-forseen flow issues. I have been searching the net, and the only reason i can find as to why blocks now come in nickel is because copper gets blockages? How is this? Can anybody please explain the difference to me? I also read that plexi tends to form stress fractures over time, causing leaks. Has anybody else experienced this? How long did it take? I really would prefer to have a see through top for my VGA waterblock, because i have had so many problems in the past from bubbles being stuck in the water channels of the block due to the orientation of the block in the case and its relation to the water flow. Is there any other clear block cover that is not prone to cracks?