I ordered the 5870 Thursday, so it should be here Monday and I'm freakin' pumped. But, I didn't realize that the card is supposed to be longer than the 8800GT (my current card), which barely fits in my case. Now I'm kind of worried. Anybody with the Antec 900 own the 5870 yet?
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The 5870 is at 10.5" length, a GTX 295 (at 11") fits on an antec 900 with like 1-2 inches left over. So to answer your question, yes it will fit. As long as you don't have your Harddrive next to your GPU, it will fit quite nicely.