Out of curiosity, will 400w be enough I've got a Corsair 400W psu, will it be okay with this: Core i5 750, 4gb (2x2GB) DDR3 RAM 4 HDD's, ATI Radeon 4830 GPU 512mb, 4 System Fans ( CPU, Exhaust, intake, roof ) Wont be overclocked as main use is for work and i want reliability over performance as i can always upgrade again next year, i do play some source games though l4d2, tf2 etc. Cheers.
Corsair make very high Quality PSUs, for yours it should be no problem to handle your stuff, just like M7ck said. Still, watch out for lower quality PSUs as they will quickly fail under a load like that.
Check this out: http://www.enermax.outervision.com/ Just add all the parts of your system and be surprised how little power you need to run this rig. Some 300 Watts, if your PSU is not worn out allready, e.g. did not run 24/7 for the last two years. And your PSU would actually aswell support, to change your GPU from a 4830 into a 5850, which would result in some 350 Watts. People most usually totally oversize their PSUs.
Neither do you want your PSU running at only 50%. A 80+ PSU should be running between 80 and 90%, if you squeez every bit of power out of your hardware. That's where your PSU will be working most efficient. 80% of the time, when you're surfing the web or watching a film for instance, the load on your PSU will only be some 30%. So calculating with 90% as a threshhold will be just fine and that's exactly what Enermax or any other manufacturer is suggesting on their site or whitepapers.
The suggestion is a bare minimum. Recommending something your current hardware takes to 90% capacity is foolish as any future upgrade with more power draw means a new PSU every time. Power rating also degrades over time.
Not necessarily. If you calculate the peak power requirements at 90% (I actually prefer to use 80%) then your average power usage is likely to be 60 to 70% for gaming and and probably in the order of 30% for internet surfing which still gives a reasonable amount of headroom. That coupled with the likelihood of an upgraded cpu and/or graphics cards requiring less power than the one being replaced means that you can often retain your existing PSU. It does, however I am running a P4 with a HD3870 on a 350W Dell PSU which is 7 years old. The system draws around 250W to just over 300W and despite my expectation that the PSU will die at any moment it is still hanging in there. I am touching wood as I type this post.
that 400w supply will be living on borrowed time, 4 HDD's will punish it, even if the PSU is corsair. I think the VX400 is done by CWT, cheaper OEM unit, and the CX400 is a seasonic which should do nicely
The 4 HDDs will add another 50W or so. Corsair do claim that their PSU can continously deliver their rated power. Nothing like putting them to the test.
its mainly the surge in current at start up that gets tests the PSU, 4 HDD's spinning up can be considerable loading on top of everything else. I once killed a 350W antec supply with just 3 HDD's
I certainly wouldn't expect much more than 20W for each HDD at spin up. That should be balanced by a low loading on the GPU. The 7 year old 350W Dell PSU I mentioned before is running 3 HDDs. One Maxtor 7.2K and two WD Raptors.
thing is were looking at over all wattage, there not all single rail PSU's. So my arguement still stands true, 4 HDD's on the same rail as the GPU would be enough to cause stresses.
Quite right, if a rail is overloaded it will cause problems but that really comes down to crap PSU design and I would have expected better from Antec. Don't forget that a PSU (or a single rail on that PSU) can be driven beyond its continuous rated power for a short period without causing harm. As long as the overcurrent protection is not operated. EDIT: Having given some more thought to Burnout's comments about multiple 12V rail PSUs it would probably be prudent to check the capacity on the rail or rails powering the HDDs. Don't believe there will be a problem but wouldn't do any harm to check.
