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New psu

  • Thread starter Deleted whining member 223597
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D

Deleted whining member 223597

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I need/want a new psu. I would like fully modular but partial(like the hale not like the antec 1200). It will power an oced i7(to 4ghz I think) and most likely an hd 7970/gtx 680 when they come out. Maybe a physx card as well. No sli. Or xfire. Now it needs to be able to power 4 MODIFIED panaflos, for reference my current pcp and cooling 750 can't power them up, have to use an extra psu just for them. I will have those 4 and 6 other fans that need to be powered and a swiftech mcp 355.

I don't like cutting it close, so a bit overkill is fine. Budget is around$ 200.
 
Corsair AX650 or Seasonic X660. Why do you say your current 750 watt cannot power them? Does connecting them cause the power supply to shut down, or do the fans simply not run, but everything else does?
 
It will start until it gets to the panaflos when it just stops and powers nothing. I think modding them increases their startup voltage.

And tbh im not a believer in cutting it close, ill rather have an overkill psu that runs at let's say 50-60% which is the butterzone of efficiency.
 
What do you mean start until it gets to the panaflos? Everything should start up at the exact same time, the power supply delivers power to every component at once, not just one at a time. Unless you disconnect your panaflos or have them on a delayed timer.

If you really want to run at 50%, then you want a 1000+ watt power supply. Otherwise, a 650 watt power supply will handle that setup with plenty of headroom, unless your panaflos are pulling 20+ watts each.
 
I guess it tries for a second and then stops trying because the motherboard lights up 2 leds(memory and something else) and that's where it stops. I think the noctua fan spins for a second and then stops. With the panaflos disconnected the rest starts up fine.
 
fans pull very little power, it sounds more like they have a short in them somewhere.
 
Then you don't know panaflos? They are 12V fans, modded I think 9V but pull more amps or something at startup.

And they run fine with a seperate 300watt or so psu just powering them. (Using this mobo connector with the 2 pin thing to start up that psu).
 
They still pull comparatively much less power than a CPU or a graphics card. I think it's the 9v mod that the power supply doesn't like, since that isn't a standard output. Unless, of course, the mod is just a resistor, then I'm not sure what's going on there. The highest speed Panaflo pulls 6 watt that I can find, which is about the same pull as a hard drive (hard drives pull 5-10 watts). Have you tried running the fans without the mod off of the pc power and cooling power supply, or connecting them after your computer has started up?
 
Once they spin, yes they don't take much power, but the startup requires so much power or amps. If I spun them each by hand(impossible since they are in the radiator in the my drive bay area) the power supply could handle them, its just the startup.
 
xIronCrossx said:
Then you don't know panaflos? They are 12V fans, modded I think 9V
Click to expand...
Can you explain exactly how they have been modded? If the "7V trick" (connecting the fan between 12V and 5V) has been used and your system has a low 5V load it's possible that they are been putting spikes on the 5V line which are causing the system to shut down.
 
plugwash said:
Can you explain exactly how they have been modded? If the "7V trick" (connecting the fan between 12V and 5V) has been used and your system has a low 5V load it's possible that they are been putting spikes on the 5V line which are causing the system to shut down.
Click to expand...

I think this is it.

http://www.performance-pcs.com/cata...mage_scroll&products_id=423&image_scroll_id=0

That is the picture of the cable, so what I did was I put the black cable on the furthest away from the red one. (Instead of being next to each other, they are in the opposite sides of the cable, so 2 spaces inbetween)
 
So, the red cable is on the yellow wire for the molex, and the black cable is on the red cable on the molex (two middle are empty). That is the 7v trick, and is likely what is causing your power supply to fail on startup, it not being able to handle the current through the 5v rail. If you had it as the regular setup (12v), then your current power supply would be able to handle those fans just fine.
 
Tsumi said:
So, the red cable is on the yellow wire for the molex, and the black cable is on the red cable on the molex (two middle are empty). That is the 7v trick, and is likely what is causing your power supply to fail on startup, it not being able to handle the current through the 5v rail. If you had it as the regular setup (12v), then your current power supply would be able to handle those fans just fine.
Click to expand...

Then it would sound like a jet engine is going off next to me. There is a reason why I did it ;)
 
I think your mod went wrong, I've got some beefed up pans and I have a 550 powering an i7/MCP655 waterloop etc.
 
TyrantTru said:
I think your mod went wrong, I've got some beefed up pans and I have a 550 powering an i7/MCP655 waterloop etc.
Click to expand...

How did it go wrong if they work on a seperate power supply? My regular power supply couldn't even start them up without anything else connected(using a the pin thingy). I don't want a freaking jet engine as my PC, if you like it cool but I don't.

My PSU is also I think 4 or 5 years old now.
 
The first thing I would do is undo the mod, if it works fine (but sounds like a jet engine) then that confirms my theory as to the cause of the problem.

Assuming it does work the permanent fix is to mod the fans by inserting a resistor rather than using the 7V trick. To determine the value of the resistor I need to know the current ratings of the fans you have (it should be printed on them somewhere).

The problem with the 7V trick is that it takes current from the 12V line and returns it to the 5V line. Power supplies are not generally designed to sink current so if the load on the 5V line is less than the current your fans are dumping into it the voltage on the 5V line will rise. While there will probablly be protection components that limit the rise I would not like to rely on them.

I would strongly advise against using the 7V trick in modern systems, particularly with large high power fans. 5V load in modern systems is far lower than it used to be.
 
Rather than getting a resister, I would just straight to a fan controller, with a rheostat one being the preferable controller. Much simpler, and you would be able to use a wide range of voltages. Sunbeam 4 channel 20 watt controllers typically costs ~$15-20.
 
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