I've spent the last 2 months with a major headache from my new build. I just wanted to throw a word of caution out there. I couldn't get my Asus P6X58D Premium board to reboot or suspend/hibernate (it would just hang with no screen when trying to reboot). I heard some things about it possibly being my ATI card... swapped for a GEFORCE with no positive results. Tried a dif brand of memory, tried RMAing my motherboard, tried reseating my CPU. No help what soever.
I found out today that Enermax PSUs have a feature called Cool Guard which keeps voltage to the fans for 1-10 minutes depending on your computers temp AFTER you have powered down. Well because of this I had to wait for 1-2 minutes (on average) before it would boot back up. This seems to only be a problem so far with newer Asus boards. Even restarts out of BIOS would fail. If you don't mind having to toggle off the PSU when restarting it isn't a huge deal (most people have their computers in suspend or hibernation for much longer than 1-2 min) but I found this really annoying.
Apparently there is no way to remove the feature either. Today I purchased an Antec 750w to replace my Enermax and put the Enermax on eBay. Just wanted to throw out a word of caution to anyone facing a similiar problem.
PS I also have seen people having the same problem on the forums with different brand PSUs so this may be a more common thing in the future.
Mine is a Enermax Infiniti 720 Watt modular (don't remember the exact model num) but I know a bunch of their PSU's use cool guard... I am not saying they wont work on any ASUS board but I read a few people with the same problems... mine is a P6X58D Premium.
I checked several references. The older technical reviews are quite favorable but there is no mention of problems with the Cool Guard feature. User comments are a mixed bag and there are complaints. Suggest you contact Enermax technical support.
I have an Asus Sabertooth 55i motherboard. The motherboard does not shut down completely. The board still draws power from the psu. There are led's on a power switch and a reset switch right on the motherboard. They remain lit all the time. The only way to shut down completely is to turn off power to the psu. Luckily I don't have to reach very far.
EDIT - Forgot to add that I don't have any problems with my psu fan.
I know that it always has power to the constant as my motherboard has the built in power/reset switches too. Forgive me for not knowing the technical information to describe what it is doing but I know it is the cool guard feature doing it as when I let it sit for a minute or two after the fans stop it will power up fine. On top of that when I cut the power from the PSU (with the toggle on the back) after the machine has powered down the speakers pop just like they would when the system is hard powered off. I can give you the 100% answer as soon as my antec PSU comes but I can guarantee this was my problem as others have replicated it.
it sucks too because the psu is really nice... I love the modular feature. The antec one is modular too but I am going from like 6 or 8 ports down to 3 or 4 which will leave me with less expandability options here. Most likely it will be fine but I would really have liked the Enermax to perform perfectly.... I did contact tech support btw... I am waiting for a reply. I should have mentioned that Asus and Enermax both admitted this was an issue to someone (I can't remember where I saw it). Asus said the board would never support it and you would have to get a new power supply and I think Enermax just blamed Asus.