Is THIS 500w good enough for Q9550 + GTS250?

[bushy777]

Hi all

My brother is reporting that his PC suddenly hangs after some minutes of play. Games: NFS Shift, Ghost Recon II, Thieve. If not gaming, the PC is stable.

We have upgraded from Win XP SP3 to Win 7 (32-bit). Didn’t make any difference.

He has following setup (2 months old):
MB: Asus P5P43TD
CPU: Core2Quad Q9550
Graphics: Nvidia GTS 250
RAM: 2 x 1GB DDR3 (Patriot)
HD 1 x Seagate 500GB
1 x DVD-RW

PSU: KNEX (Unfamiliar brand – even here in South Africa . .. J )

PSU ratings on lable:
+3.3v - 32A
+5v - 30A
+12v1 - 17A
+12v2 - 16 A

After reading jonnyGuru’s sticky about split rails, I am wondering if PSU is not to blame.
The fact that there are 2 ratings for +12v, implies that there is a dual or split rail, is that correct?

If my calculations are correct, q9550 alone requires 18.25A at full tilt (219w / 12v = 18.25A). Meaning that neither “channel” will be able to provide adequate power. GPU requires 12.5A max (150w / 12v = 12.5A). Do I understand it correctly? If it wasn’t for the split \ dual rail config, the PSU may have been adequate? Do I understand it correctly?

I do not know which connectors run on which rail . . . ?

Do you guys think it may be PSU, or must I suspect something else as potential culprits for system lockups?


Thanks

 

[TemjinGold]

Err... where did you get 219w for your q9550 alone?

 

[Jd007]

The 12V rails of that PSU seem a bit weak, so it could be your problem. I would probably opt for one from a better brand (Corsair). Remember wattage label isn't everything and that smaller brands tend to be over-confident in their wattage labels.

And yeah the Q9550 is a 95W CPU, far from the 219W you mentioned. How long have you had the PSU for? Below average quality PSUs have a much shorter life than the higher end ones. As for which part draws from which rail, both the CPU and the GPU (which together use the most power in your computer) draw from the 12V rails.

 

[ocsid80]

I have used Q9550 with a no name 450W PSU for half a year without any problems.
If I remember it correctly, the 12V rails were capable of delivering 16 A.

 

[Meghan54]

The difficulty you're having is from making several assumptions.

First, just because the two rails can deliver X amps per rail, the combined output is just as important, if not more important. You simply cannot add the two +12V rails to come up with what the power supply can deliver on the +12V rails combined. My guess is that the total delivery on the combined +12V rails is well below what they add to.

Second, even simply adding the two rails together gives you 396W of +12V power, a sign that the power supply is an older design. Much newer designed power supplies, even with multiple rails, can output close to total rated power just on the +12V output. Go search out current model Corsair, Antec Earthwatts, and others to see this. You'll find they can put out 90% or more of the rated unit's output on the +12V rails.

My guess is that the culprit is, indeed, the power supply but not because of having two rails. It's instead because of it being an old designed power supply, designed back when the +3.3V and +5V rails were the rails that were heavily used for use by the computer and the +12V rails were there for auxiliary use.

 

[M0RPH]

I checked the first 3 GTS250 reviews that came up in a Google search and this is the LOAD power consumption they measured:

i7 965, GTS250 ~240
QX9770, GTS250 ~265
i7 965, GTS250 ~250

Even a generic 500W psu should be able to handle those kinds of loads. Maybe there is something wrong with the psu but I wouldn't rule out some other issue.

 

[nipplefish]

It could also be that the ATX12V connector and the PCIe connectors are on the same rail.