Insufficient PSU power?

i searched the forums for anything like this but couldnt find anything. anyway, heres how it goes: i recently bought an ATI X1950 Pro 512MB AGP and Akasa 500W PSU to run it, since my old one didnt have the wattage to power it. but, after numerous tests, i find that the card hasnt improved my PC's performance over the other one (ATI X800XT PE 256MB). im wondering if this is down to my PSU not having enough amps to power my card properly. the PSU specs say dual 12V rail at 18amps each, the X1950 apparently needs 30 amps on the 12V rail to run. after doing some research, im a bit confused by people saying the ampage on a dual rail is combined, so that would mean i have 36 amps on the 12Vrail. but others say that is not the case, could this be the cause of the lack of improvement? i also read reviews on the card from people with very similar systems to mine and they reported a huge increase in quality, even from upgrading practically the same GFX card. my PC specs are as follows

Intel Pentium 4 3.06ghz Prescott processor.
Windows XP Home SP2.
ATI X1950 Pro 512MB x8 AGP. (upgraded from an ATI X800XT Platinum Edition 256MB)
2GB DDR2 PC-3200 RAM
ASrock P4i65G Motherboard with the Intel 865G chipset.
Akasa Pax Power 500W PSU. (graphics card required a minimum of 450W according to the specifications)
latest video drivers.
running in 1440x900 resolution. (i tried 1024x768 and it was still really slow)

any advice on this i would greatly welcome since i am at a loss on this one. thanks guys.
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More about insufficient power
  1. Although not likely, it could be a bottleneck of the CPU. But I highly doubt it. The PSU is a brand I myself am not to familiar with, so I'd say try a better brand. There's a PSU guide I beleive in the CPU & Componets section. Check that out. Infact, here's the link.

    There's a wealth of information in that section, especially at the bottom.
  2. awesome thanks mate. thats a big read! i just thought of something, i dont know alot about PSUs but would it possible to run 2 independant molex connectors into the card to give it enough amps? for example: the PSU has 2 seperate sets of molex cables coming out of it, each with 3 molex plugs each, for a total of 6 molex plugs, the card is only connected to 1 set right now, if i pugged both sets into it, maybe that would work? is that what dual rail means? sorry if this is confusing., im not too sure on how to sum it up.
  3. The problem is not the PSU. If you were having issues with the PSU, then your PC would be crashing or Windows will just freeze.

    Your problem is most likely due to driver issues, or your Windows Registry is so large, it is causing performance issues. Another problem could be your CPU is overheating. When a CPU overheat it clocks down to prevent the CPU from frying itself. Another cause could be your hard drive is too fragmented.

    As a last resort, you should do a clean install of Windows which can work wonders to increase performance.

    I repeat, you do not have a PSU problem.
  4. I highly doubt he needs to reformat. It clearly sounds like power given he is REALLY pushing it on that PSU. By no means am I a PSU expert, but I've pushed systems close on power requirements before. One rule of thumb that I've learned over the coarse of time is this: Wattage doesn't mean everything. Also, if it's a Dual 12V Rai @ 18A each, that doesn't mean you'll get 36A on the 12V Rail combined. It's actually lower. On your PSU there is a label, it will say +12V 1 and +12V 2 @ 18A. Under that should be some amount of wattage, as an example, 400W. So, to get the actual combined 12V Rail amperage it would be 400W divided by 12, which gives you 33A. So, find your label, find the wattage, divide it by twelve, and that's your actual combined amperage. Well, that's what i was taught at least.

    As for the molex plug issue, I'm not entirely sure what you mean. Are you saying the video card has two molex connector and you're only using one? Or what? Perhaps a picture would tell us?

    In addition, not always does Windows have to freeze up or a reboot have to occur to show indications of a PSU issue; which is why I am still suspecting a PSU issue. Perhaps some other member who have higher knowledge than I, and I know they're out there, can assist you. Just trying to lend the info I know to you. Hope it helps. :)

    EDIT: Here's a picture of the +12V 1 and +12V 2 I was talking about. (Note how under them is a combined Wattage, divide that by 12 to get combined amperage on the +12V rails.)
  5. i tried my molex thingy and it didnt work, didnt think it would anyway. so, below where it says the 12V rail amps, it says +3.3V & +5V combined load = 210W, and below that it says 500W max. does that mean my PSU's 12V rail ampage is only 17.5? (210 devided by 12). it doesnt say any more than that and doesnt list wattage only for the 12V 1 and 2 as the PSU in your pic does
  6. tyrannosaur said:
    ... the X1950 apparently needs 30 amps on the 12V rail to run.

    The X1950 does not need 30 amps on the 12 volt rail. The X1950 at stock speed only uses about 66w of power, it only uses 5.5 amps (66w / 12v).
    Nvidia GeForce 7950 GT Graphics Card Review

    The 30 amps is a recommendation for the entire PC. ATI (and nVidia) doesn't know exactly what components you are using in your system, so they generally recommend something high so that even people with a quad core CPU and 6 hard drives can install a X1950 without any issue. If the X1950 were to use 30 amps, that would total 360w (30 amps x 12v). That most power than a large tv set.

    In most cases, you cannot simply combine the amps on all the rails to get total amperage because each individual 12v rail is being rated at their peak power, not constant power.

    Below is an example of the Antec Trio 650w PSU:

    There are three 12v rails, each is rated at 19 amps for a total of 57 amps. 57 amps works out to be 684w (57a x 12v), that is a dead give away that those amp ratings are based on peak not constant amperage. How can a 650w provide 684w all on the 12v rail no less. Note the underneath the "spec grid" the sticker states:

    +12v, +12v, and +12v max load: 52A

    That tells you that 52 amps is the true max amperage of the PSU, or 624w. However, that is assuming that the 3.3v and 5v rails do not draw more than 36w (624w + 36w = 650w). Since many components draw power from the 3.3v & 5v rails, like the motherboard, RAM, sound card, anything that plugs into the PCI (not PCI-e) port, and hard drives as well as CD/DVD drives, the PC will be drawing more than just 36w from the 3.3v & 5v rails. Hard drives and CD/DVD drives draws power from bothe 12v and 5v rails.

    The Seasonic S12 500 (like the one in my system) is one of the few PSU that are rated at constant amperage, not peak amperage. See the sticker below:

    Oh well, the image isn't being display so click the following link:

    The Seasonic S12 500 can provide 17 amps on one 12v rail and 16 amps on the other rail. That's a total of 33 amps. According to the specs, the 12v rails can provide 396w of power on the 12v rails. That works out to 33 amps (396w / 12v), therefore the Seasonic S12 series is one of those few manufactures who lists constant rather than peak power.
  7. Akasa is an example of manufacture who has very poor information about their power supplies. Not only do they not provide a picture of the PSU's sticker which should have all the relevant information, but their website also provides inadequate information as well.

    The only thing you know is that it is a 500w PSU with two 12v rail. Each rail is capable of delivering 18 amps individually, but I really doubt if the 12v rails can really produce 36 amps of constant amperage. I would guess something closer to 32 amps or 384w.

    In any case the PSU is not the problem since you are not experiencing restarts, freezing, or the dreaded "Blue Screen of Death".

    Uninstall your video drivers reboot then reinstall the drivers. Defrag your hard drives. Uninstall programs you do not uses any more. Are you overclocking your CPU? If so it may be overheating, thus throttle itself to a lower clockspeed to prevent itself from overheating. Lastly, reinstall windows.
  8. i have already tried removing all video drivers, restarting and reinstalling them, i havent defragged my HDD yet, mostly cus windows told me it doesnt need defragging after an analysis so will try that out, havent overclocked the CPU, recently cleared out all programs im not using too. reformatting is a last resort because installing everything on my HDD will be a pain. i looked onthe back of the box of the PSU and it says the following: Dual rail 12V ( 500W-18A and 400W-15A). no idea what this means though and why its stating 2 different wattages and ampage. the link you got there is exactly the PSU i have.
  9. Well, what kinda games do you not see an improvement in?

    Have you tried running programs like 3Dmark06 to benchmark both cards?
  10. ive tried Battlefield 2, Command and Conquer 3 and World of Warcraft. i maxed out BF 2 and it ran at about 50 fps max if i wast looking at any heavy fighting in the game, if i did, fps would drop to about 25-30. i read about people on an almost exactly the same system in some cases gettign 100fps in BF2. Command and Conquer 3 i ran several tests on. on the old card my fps would drop to around 10 when the game started getting intense, that was on the game's high settings with no AA, it has 1 higher setting but i never used it. on the new card there was no improvement in performance whatsoever. still 10 fps when the game gets frantic. then i lowered the settings to medium, and only a slight improvement, 12-14 max. then put it on absolute minimum and best fps was 15-16 during the same situation (this lead me to believe it might be the processor). on WoW its the same as with the old card, if you dont play WoW, when things get intense in it, it can slow your PC to a crawl. i havent tried 3Dmark06 but i ran 3Dmark03 on the card (couldnt find one i didnt have to pay for). and my PC scored just over 13000 on it. i never ran the test on the old card though, i might do that tomorrow.
  11. might give this a try:
    Try loading a program to display 12V (or if you have and know how to use a voltmeter connect to 12 Volt on molex connector). Run ATI tools and inable "Show 3D View". 12 Volt rail show not drop below 11.4 V (Perferably not below 11.6V).

    2. If there is a program that will display GPU Core Freq while runing a 3 D App (I think ati tray tools may work - Don't use myself) verify that infact the card is switching from Idle mode to 3D mode ( ie core freq on my X1950xt changes from 500 to 621. If this is not occuring then that is the reason poor performance.
  12. i just ran ATItool on the card and when i turned the 3D view on, the card fan starts to run at full and the GPU temperature goes up very fast, it went from 51 idle to 70 in about 15 seconds, i think it would continue to rise too. i ddint overclock it and left it on its default clock speeds. i also disabled the fan override speeds. the card has never run that hot to my knowledge in any test ive done.
  13. My 1950 XT (Stock cooler) also idles about 50 C. If I run 3d view mine reaches about 68 C within a min, It levels off at 70-71 C after about 3 Min. I have the fan controls set so that at 50 C -fan is 50%, at 60 C - fan at 75%, and avove 70C fan goes to 100%.

    I think (SOMEONE CORRECT ME IF IN ERROR). the 1950 series are ok up to 90 - 100 C.

    Have you found a way of verifing 12 Volt rail voltage.
  14. just ran the voltage tests, i found a program called Hardware Monitor. on idle the 12V display showed 11.80 volts, i turned on the 3D view and the voltage went down to 11.61 and stayed there. for some reason the fan remained at 45% until the GPU hit about 74c. i got the fan override option off. ive decided now to return the PSU anyway and invest in a "much better" one. apparently the OCZ GameXstream (or something like that) is an excellent PSU. one thing find unusual sometimes, my screen decides to go blank for a second or two, this never happened with my old card. it happened once when i hit the default button on ATItool. i thought it had pushed my GPU really hard and i had to restart the PC
  15. Well, 11.61v on the 12v rail is still within the +/- 5% fluctuation tolerance for a typical PSU.

    As for why the fan remains a 45% until the GPU hits 74c, well that's probably the default settings. I use ATItool to override the default fan settings.
  16. Wasn't X800XT PE one of the most powerful cards of the Xxxx generation? X1950 Pro was a mid range or low high end card of the X1xxx generation, so it might not be significantly more powerful than X800XT PE in any case.

    I just checked VGA charts, X800XT gets 15.3 fps and X1950 Pro 17.1 fps in Oblivion (outdoors) at 1280x1024 / max quality.
  17. hmm, not sure about that. the X800XT PE is powerful, but its a very old card, the model i have is a late 2004 i think. the X1950 Pro was released in early 2007 i think. i also got the 512MB, 500/1400 version, my X800 is only 256MB, 420/1200 i think
  18. Is it possible that your AGP aperture size is out of wack in BIOS?
  19. ive played with the aperture size, hasnt made any difference. one thing ive found intersting is i took out the 500W PSU and put in a 400W one of the same make, and it hasnt made any difference, my PC hasnt even slowed down even though the card needs 450 minimum apparently
  20. Yeah I think you just proved it isn't a power issue. Like people have said, you would see crashes and unstability if you didn't have enough juice.

    For Morton's reply, I think they used PCIe versions of the cards in the 2007 VGA charts. Plus the setup was a core 2 CPU. You do have a point though, the X800 XT and X1950 Pro don't have too large of a gap. I would think with a the 3 years diff. the 1950 would KILL the 800 though.

    I have the same chipset / socket set up that you have. The 865G chipsets and 478 sockets are pretty outdated now. I know that people are saying that the CPU shouldn't cause a bottle neck but I am curious if the card can run better with more current chipsets / multi-core CPU. I hope that I am wrong and you can get that thing crankin but I have a feeling that the mobo setup might be too far behind the times.
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