05-30-2013, 09:46 PM
well, that's not necessarily true.
yes, the 6990 draws an insane amount of power, and is unbelievably hard to cool. but the 5970 was a fantastic card, and was quite manageable. i have four running right now that have been under 100% load for a couple months straight, and their temps are staying right at 74-77C with the stock coolers.
the reference design 7990 seems to be a lot better thermally than the 6990. it draws about 75W less watts than the 6990, and because its heatsink spans the entire length of the card and features five copper heat pipes, it seems to run a lot cooler as well.
in fact, every benchmark and review i've read so far shows the 7990 actually running cooler than a 7970. now i have yet to verify these claims, as newegg can't seem to keep them in stock long enough for me to purchase one, but it does in fact look quite promising.
that said, there's two reasons why you can only run four 7990s in the tyan chassis:
1. driver only supports 8 devices
2. not enough power
now, #1 may not be true anymore, but no one has yet to successfully verify. i tried a few months back, and the driver recognized 12 devices, but x11 crashed every time it tried to load.
with #2, the tyan chassis has a maximum output of 2400W @ 240V, or 2000W @ 120V. if #1 were no longer true you could potentially put a fifth card in there, but that would be pushing it.
yes, the 6990 draws an insane amount of power, and is unbelievably hard to cool. but the 5970 was a fantastic card, and was quite manageable. i have four running right now that have been under 100% load for a couple months straight, and their temps are staying right at 74-77C with the stock coolers.
the reference design 7990 seems to be a lot better thermally than the 6990. it draws about 75W less watts than the 6990, and because its heatsink spans the entire length of the card and features five copper heat pipes, it seems to run a lot cooler as well.
in fact, every benchmark and review i've read so far shows the 7990 actually running cooler than a 7970. now i have yet to verify these claims, as newegg can't seem to keep them in stock long enough for me to purchase one, but it does in fact look quite promising.
that said, there's two reasons why you can only run four 7990s in the tyan chassis:
1. driver only supports 8 devices
2. not enough power
now, #1 may not be true anymore, but no one has yet to successfully verify. i tried a few months back, and the driver recognized 12 devices, but x11 crashed every time it tried to load.
with #2, the tyan chassis has a maximum output of 2400W @ 240V, or 2000W @ 120V. if #1 were no longer true you could potentially put a fifth card in there, but that would be pushing it.