any psu experts, need some help

Nickolp1974

Nickolp1974

Nickolp1974

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trying to determine a lock up problem i get with overclocking my 7970 lightning, i get lockups when running benchmarks over 1325 v, temps are fine at this v.core can someone tell me if my psu can handle this here is a lnk to a review and specs on rails

http://www.bit-tech.net/hardware/2007/05/10/700w_to_850w_psu_group_test/3

lightning at stock speeds/volts consumes approx 422w @100% load

i am connected to psu via the 2 8pin connectors, 1@top and 1@bottom.

looks like on the chart my psu can only handle 18A and a max power draw of 216w on 1x 12v rail.

would like to have a go at a watercooling set up once blocks are available, so my question is, do i need a new psu????
 
That 422w would be total system power not just the card. Even my GTX480 does'nt come anywhere near that.

Your psu is more than enough for even another 7970 plus watercooling and still have some power left over. You have 6x 12v rails of 18A each totalling 720w.
 
check this, the psu they used on the test you linked:

http://www.techpowerup.com/reviews/Antec/HCP-1200/2.html

its got 30A on each 12v rail, spread over 8, not 6 like yours, the rest is pretty comparable.

have you tried working up from the defaults to see where you start to encounter issues ?

also worth noting the following on the review you linked, so it might NOT be just a graphics issue:

Unfortunately, despite the fact that the Cooler Master is a great looking unit with a very quiet fan it consistently failed as a PSU as the load was increased. The 5V rail is predominantly used by hard drives and optical drives, but also a few motherboard components make use of it too.

With a low 5V rail you can suffer cold boot issues as your drives compete for juice when they spin up. At 100 percent load we also see a low 3.3V, and consistently throughout we have a borderline acceptable 5V standby voltage.
 
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mp260767 said:
check this, the psu they used on the test you linked:

http://www.techpowerup.com/reviews/Antec/HCP-1200/2.html

its got 30A on each 12v rail, spread over 8, not 6 like yours, the rest is pretty comparable.

have you tried working up from the defaults to see where you start to encounter issues ?

also worth noting the following on the review you linked, so it might NOT be just a graphics issue:

Unfortunately, despite the fact that the Cooler Master is a great looking unit with a very quiet fan it consistently failed as a PSU as the load was increased. The 5V rail is predominantly used by hard drives and optical drives, but also a few motherboard components make use of it too.

With a low 5V rail you can suffer cold boot issues as your drives compete for juice when they spin up. At 100 percent load we also see a low 3.3V, and consistently throughout we have a borderline acceptable 5V standby voltage.
Click to expand...


have had many cold boot issues, solved double post(asus board) but sometimes will not boot, saying OC failed, restart and all is fine and also had 1 HDD go(not uncommon but who knows the cause)
 
PSUs will tend to have PCI power on separate 'rails'. Each PCI power cable will provide 150W for 8 pin and 75W for any 6 pin connected. The PCI express interface will also provide 75W which comes from the 24 Way ATX connector. These may all be on separate 'rails' anyway.

PSUs these days don't have true rails. Usually it's just one big chunk of 12v with each artificial rail individually limited. You could draw 18 Amps from rail one and nothing from the other 5 and nothing untoward would happen. In some cases there is no current limiting going on any rail but they still advertise limits on the rails so it conforms to an older ATX spec.
 
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thanks tealc/mp260767 for the info

so if my psu is approx 80% eff does than mean i have 680w to play with basically????
and i'm using 620w(gfx@stock and [email protected]), does this mean i have 60w left to play with???
so with my current spec theoretically i'm running my psu @91%???????????????
 
The PCIE 6+2 spec is 150W / 13A@12V.

A card with two PCIE8 pins will take a maximum of 450W (150W x 2, plus 150W from the bus) unless it's out of spec. CPU takes at the very most 150W, so if you had a uber card that would max out the PCIE standard and a uber CPU, you would be needing 600W. The 2500K + 7970 is nowhere near that.
 
Nickolp1974 said:
just did a rough calc of my pc's power requirements and it comes to 620w with gfx at stock settings
Click to expand...

There is not a chance that your pc will pull that much. Your cpu is more efficient than mine as is your graphics card yet the max i can get mine to pull (from the wall) is 412w and that's by running linx and furmark both at the same time.
 
Just used a rough calculater which i found on the net, most probably inaccurate then. Just trying to rule it out. But what does concern me if you look at post #6 the quote then my answer. Did not even think about the psu with that one
 
Taken from thermaltake website recomMends 505w but to quote

The total PSU Wattage this tool recommends will give a general idea of the range of continuously available power (not peak power) at which you should be looking. But if you are planning to build a high end gaming system, total Amperage available on the +12V rails—and how that capacity is distributed—could be as or more important than total Watts of Power


4 * Electrolytic capacitor aging. When used heavily or over an extended period of time (1+ years) a PSU will slowly lose some of its initial wattage capacity. We recommend you add 20% if you plan to keep your PSU for more than 1 year, or 25-30% for 24/7 usage and 1+ years.
* * See our Terms of Service for details.

Had my psu for 5 years and its on nearly everyday for a couple of hours, my amperage is low compared to modern psu's, please advise.
 
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Just don't want to advise you to get a new psu only to find out you still have problems. With the cold boot issues and needing a double boot sometimes i would be tempted to take a look at the motherboard. Does it still have problems with everything at stock?
 
Does not do the double boot after changing a few settings but occasionaly just wont boot first time, either hangs or it says oc failed. So i just reset it and alls fine with oc settings and before you ask it can run prime for 12 hours and no probs and done memtest and no probs.
 
Software readings of PSU voltages are unreliable.

If those voltages were correct your PC wouldn't be working at all.

You really need the proper equipment (which I assume you don't have) to test the PSU voltages.

Have a look in the BIOS as there are usually reading there.

It's not perfect but it may give you another perspective.
 
just checked bios and its showing 12.096v
are there any other in windows software where i can check this, i know it will not be accurate and your assumptions are correct i dont have the equipment to test.
 
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