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Big question: DOES power supply affect performance?

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November 27, 2007 10:36:02 PM

Well its a simple question but I get different answers depending who I ask:

Does PSU have an effect on gaming performance?

My rig:

Compaq Presario:

Vista 32
Athlon x2 4400 2.3 mhz
2 GB ram
Integrated 6000 model videocard - upgraded to XFX-Geforce 8800 GT Alpha Dog version.

I get 5.9 on everything except 5 for CPU and 5.4 for harddisc in the Vista check.

The recomended PSU for the new card is 500w but I only have a 300w in my system.

Now I play Crysis but get fps between bout 15-30 depending on the action on all medium 1024 resolution which is a laugh I think. can't even play High due to laggin.

Any chance my PSU is bottleneckin the performance here? Would my fps be likely to increase if I got a 500w PSU?

Ps - i have the new drivers for my videocard
a c 665 ) Power supply
November 27, 2007 10:43:39 PM

If the GPU is starving on power it can get affected. The main question here is what is the amperage on your + 12 volt rail? It should be on a sticker on your PSU
November 27, 2007 11:14:37 PM

I think the PSU could definitely be effecting things.

The CPU and PSU alone could be pushing 250w.
Toss in Fans, RAM, Mobo, etc.... and you are nearing 300w.

Toss in the fact your system is not new and the PSU may not even deliver the full 300w anymore.

There is not any guarentee that a new PSU will help, but there is a chance.
Related resources
November 28, 2007 12:31:14 AM

You could check your voltages in the bios or with SpeedFan or another util such as MBMonitor. If the 12v rail is +/- 10% more/less from 12v you could have a problem there. That's a 10.8-13.2 volt range. I've had a few PSU's that eventually stopped providing power to spec, and caused hard system freezes. I've never personally seen FPS problems like you mention in relation to the PSU, but it won't hurt to check. Heat and power can do really bad things.

Edit: A volt meter into the molex power connector or the power leading to the motherboard will be more accurate.
If possible, test under load.
November 28, 2007 12:54:42 AM

compaqs are always underpowered for major upgrades, although the graphics card recomends 500w, theres more emphasis on the amps on the 12v rail, power supply does not affect performance directly but a better power supply can usually power up better components... to be safe try a 450watt corsair, its know to power 8800gt well
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
November 28, 2007 1:23:42 AM

Most deffinately.If your power supply is too weak,(which yours is),then you'll get all kinds of problems,including possibly burning out the whole computer.But in all likely hood,it will just crap out itself.If the recommended PSU is 500watts,then make sure it has at least 28amps on the 12volt rail.Goodluck.

Dahak

M2N32-SLI DELUXE WE
X2 5600+ STOCK (2.8GHZ)
2X1GIG DDR2 800 IN DC MODE
TOUGHPOWER 850WATT PSU
EVGA 7950 GX2 550/1350
SMILIDON RAIDMAX GAMING CASE
ACER 22IN WS LCD 1680X1050
250GIG HD/320GIG HD
G5 GAMING MOUSE
LOGITECH Z-5500 5.1 SURROUND SYSTEM
500WATS CONTINUOUS,1000 PEAK
WIN XP MCE SP2
3DMARK 05 13,685
November 28, 2007 1:46:04 AM

If your PSU is supplying enough power, every thing should be fine. If it isn't, yeah it might be "bottlenecking" the pc, although that's probably not the term for it...
November 28, 2007 6:03:14 AM

I'd advise that you don't let that 300W powersupply stay for long. Get a new powersupply as it has the very real possibilty that the PSU would burn itself out. Though as others said, look first at how many amps the 12V rail could provide. It is possible that you get a 500W psu but still not enough amps to provide adequate power.

An 8800GT consumes somewhere around 170W at load if I remember correctly. So even if your powersupply could provide at 90% efficiency (only the really high-end powersupplies could achieve this) that would leave only 100W for everything else.
November 28, 2007 6:55:27 AM

from a theoretical point of view the psu shouldn't effect performance - either it will have sufficient power for the system or it will crash, unless it has safety features like when the external power plug isnt connected, giving a warning.
November 28, 2007 7:04:48 AM

The power supply won't have a significant affect on performance: The system would CRASH if the voltage dropped low enough to have a large effect.
November 28, 2007 7:38:05 AM

To me a big YES! system would crash or cause error if not correct voltage is given to your PC. You can check that at BIOS.

12V = should be 12v or 12.2 not 13v, most cheap PSU is under 12v
5v = 5v or more but should not reach 5.5v not 4.8v (some PSU does)
3.3v = 3.3 or more but not reach 4v
This affect games...usually heavy games will crash. Even Warcraft DOTA, errors will appear based on my experience as I changed my PSU this problems was avoided already.

@Crashman
lol 42037 posts already.... You should be called man of the ancients. [:pogsnet]
November 28, 2007 1:33:32 PM

rolli59 said:
If the GPU is starving on power it can get affected. The main question here is what is the amperage on your + 12 volt rail? It should be on a sticker on your PSU


Ok I will have a look - any rules for how big amp on +12 for a 8800 GT?
November 28, 2007 1:36:33 PM

imrul said:
compaqs are always underpowered for major upgrades, although the graphics card recomends 500w, theres more emphasis on the amps on the 12v rail, power supply does not affect performance directly but a better power supply can usually power up better components... to be safe try a 450watt corsair, its know to power 8800gt well
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


By "power up better components" u mean things will float better or huh? Don't really get it if at the same time the fps won't be boosted by the better PSU???
November 28, 2007 1:40:02 PM

Crashman said:
The power supply won't have a significant affect on performance: The system would CRASH if the voltage dropped low enough to have a large effect.



That is what I have heard to and it seems logic I mean either it provides the power or not. But also in this thread ppl seem to disagree quite a lot - some say the PSU actually "bottleneck" due to low amp or watt others like you that it has no influence...hard for a technoob like me to figure things out :sol: 
November 28, 2007 1:59:25 PM

Anyways have made a 3D mark now and the result was:

So 7674 overall and CPU score of 1646 maybe the CPU is the bottleneck for crysis even though fps of only 15-20 when action on Med level is extremely lousy I think....But now I have a 3D mark test - kindda weird test I reckon especially that only one other have a similar system - will do another when I have a new PSU with lotta amp :) 
November 28, 2007 2:17:10 PM

I believe that the Amps required on the 12v rail for an 8800gt is 24.

Also, systems do not necessarily crash due to being underpowered. It is often the case that some computers will experience a 'bottlenecking' effect when put under stress. I experienced this while I was still using the stock psu that came with my case. Games, utilities, etc would run fine until it was apparent that the computer was using power that exceeded the capacity of the psu, ie. during games. This happened most often in battlefield 2 and 2142 when there was a lot of artillery on screen (which I've been told uses both gpu and cpu to create the particle effect). The system did not crash, but my frame rates would drop into the teens. This would even happen in Quake 4 when I had the graphics quality turned down. I've now got a psu that can more than handle my system components and have yet to experience the same problems, my frame rates stay reasonably consistent no matter the situation.

Keep in mind the fact that gpu's and cpu's do not draw the maximum voltage from your power supply at all times and that their specifications quote the maximum power that they will draw. This will make the 'bottlenecking' idea easier to understand.

Your gpu uses significantly fewer amps than does mine, so you should be able to get away with purchasing a less expensive (but still high quality) power supply. Corsair, Antec, Seasonic all sell power supplies that are reasonable in amps, wattage and price. Do yourself a favor and stick with quality brands and you shouldn't see performance drops due to a instable psu.
November 28, 2007 2:58:25 PM

The first psu you've listed (linkworld) appears to be pretty poor quality. The listing states 65% efficiency, which is pretty darn low. I've never heard of Enlight, which doesn't mean the psu is crap, just that I've got no idea. There are psu's from Corsair and Antec on the site you've been using that are in a similar price range to the Enlight psu. Either would be a good psu. Links;

http://www.pc-lager.dk/vare-oversigt.php?varenummer=309...

http://www.pc-lager.dk/vare-oversigt.php?varenummer=308...

There is also a guide that ranks psu's into teirs that is very useful. Link:

http://www.xtremesystems.org/forums/showthread.php?t=10...

Hope this helps.
November 29, 2007 5:09:20 PM

Hmm, I gotta bitta impatient and bought a Raptoxx 600w: specs are +3.3V 18.0 A +5V 28.0A 12v1 18.0 A +12V2 18.0A

This PSU was actually more expensive than the mentioned same price range as a Cooler Master M520 Real Power Pro Modular 520Watt about 150$ but they only had the Raptoxx in my local store.

Yet no improvement fps wize so reckon it was a wasted buy somehow and Crysis can go blow me....lol

Wonder if something is wrong with my 8800 GT???
November 29, 2007 8:41:48 PM

i would say that the problem is due to a software, driver or heat issue. check your temps, update sound and video drivers and re-install the game. if none of that works i cant help you but im sure theres sum 1 here or sum who can help

good luck

a little rant... not at the person who asked the question, just the people who told the poor guy to get a new psu when
they didnt know what they were on about!!!

i cant belive all the people here who are saying a weak psu will affect performance lol.

if you reduce the power to a cpu, or gpu with software what happens..... do your benchmarks come out slower? NO. either your pc becomes unstable and crashes or your pc will just turn its self off. the same is true if a psu is giving too little power. performance will not be affected but you can get crashes and seemingly random shut downs. unless your psu is a cheapo model with inadequate overload protection there is very little chance of physicaly damaging your pc or powersupply.

dont reply to a question you dont know how to answer
April 10, 2008 3:25:11 PM

Quote:
if you reduce the power to a cpu, or gpu with software what happens..... do your benchmarks come out slower? NO. either your pc becomes unstable and crashes or your pc will just turn its self off. the same is true if a psu is giving too little power. performance will not be affected but you can get crashes and seemingly random shut downs. unless your psu is a cheapo model with inadequate overload protection there is very little chance of physicaly damaging your pc or powersupply.


That's not entirely accurate. If there are components or software that have any sort of built-in error correction, it's entirely possible to have poor power affect performance without crashing the machine. Hundreds or thousands of single bit errors could be being resolved without any outward signs of a problem. However, depending on how the correction was implemented, it could be consuming cycles that would cause you to see a drop in performance. I admit that it's not the common occurance that people are making it out to be, but it's certainly not impossible.

I recently encountered a problem with a power supply that only caused a crash under very specific conditions, but had a very definite impact on performance otherwise. The machine would "stutter", appear to lock up for seconds at a time and then would come back and my average framerates were all over the map (and well below those of people that were running comparable configurations). Occassionally an app would crash completely, but it was very rare. I could run benchmarks, burn-ins, load simulation, etc. and it would run fine. However, when I enabled specific options on my video card and in DirectX, the machine would crash. It was *NOT* an issue of insufficient power and it was not the video card (since it worked perfectly in another system with the same drivers and software). Replacing the power supply corrected the crashes, stuttering and levelled out my framerates. It's likely that there was something marginal with the system that the power supply just made worse.

I admit that replacing the power supply was an act of desperation and *not* because I truly beleived that it was the problem. However, I switched the power supplies back and forth 3 times to confirm that it wasn't something that I was inadvertently changing in the swap. The behavior was consistent. I think that it's a question of power quality more than sheer output. But the fact remains. A power supply *can* affect performance.

With that said, don't rush out and buy a new power supply expecting it to improve your performance. If you have other symptoms of a problem, I'd seriously consider it. But Psyman is 100% correct in saying that throwing more power at the machine isn't going to help you if everything is already running smoothly.
April 10, 2008 5:14:59 PM

Further support for the "lack of power" issue.

From the NVIDIA support forums (http://nvidia.custhelp.com/cgi-bin/nvidia.cfg/php/endus...)

Quote:
The Geforce 8800GTS requires a minimum 400W or greater system power supply with a 12V current rating of 26A. While most Geforce 8800GTX users power supply meets or exceeds the minimum wattage requirements, the power supply may fail the minimum current necessary to achieve consistant framerates during heavy use of the graphics card. For a list of NVIDIA certified power supplies for the Geforce 8800GTX, please visit the following URL:

http://www.slizone.com/object/slizone_build_psu.html#ce...

Another cause for poor performance can be due to a user forgetting to connect both power cables to the graphics card. While the Geforce 8800GTX can boot with only a single power supply, to run at optimal speed, you need to connect two PCI-E 6-pin power cables to the two connectors on the graphics card.


and

http://nvidia.custhelp.com/cgi-bin/nvidia.cfg/php/endus...

Quote:
When the graphics card is not receiving enough power, it reverts to lower clock speeds to prevent your PC from locking up.


Hopefully this resolves the "power supplies can't affect performance" controversy once and for all. (better late than never :) 
April 10, 2008 5:45:12 PM

There's actually another way PSUs can affect overall system performance. Why is it that no one tries insane overclocks with a generic PSU? A rock solid PSU would not limit OC'n capabilities... where a strained PSU easily could limit an OC. Just a thought.

That and the the GPU throttling.
September 14, 2009 1:09:30 AM

hye guys...
plzz i need your help,
i'm currently using a cpu and these are my specs : these WERE my cpu specs before :

intel D945PLRN motherboard same motherboard
ram 2gb 512 mb ram
intel dual core 2.66ghz same
nvidia geforce 9600 gt 512 ddr3 256bit ati radeon ( forgot the model) 256 ram ddr2
240gb HDD same
windows XP SP2 system same

before this, i've been playing a lot of games include prince of persia, devil may cry, dynasty warrior, PES, NFS ( from MOst wanted to carbon ) and evrything went well without any lagging...using my old graphic card. then i tried to play DMC 4, at that time my ATI couldnt support, so i chose 9400gt. it went quite well except it is lag..i know that game in high graphic..
then i bought the last remnant, still lag.so i chose a new one 9600gt.
i thought by changing the graphic card, i would have no prob with lag anymore.but i was wrong.
the games i played, kept getting slower...earlier in the game all is smooth and fun to play..but after a few minutes, it lag again...
and now even games with low graphic is slow...even PES, most wanted, guitar hero. while before i change into 9400 n 9600gt, this game is really smooth.
even at highest graphic setting in 9400gt.
now there are no difference wheter in lowest or highest settings.

1) so some one plzz help me..
i wanna know why..
is it my processor?
because the utilities sofware i installed says that my processor temperature is above limit.but my computer doesnt shut down by itself while playing games.
plzzz

2) ok let me explain a bit detail...
before this i've been using ATI radeon GPU which last for more than a year.
using this GPU, i've been playing guitar hero 3 at medium settings, most wanted, carbon, DMC 3, dynasty warriors, pro evolution soccer, with no lag at all.
but most of them at medium or almost high graphic settings. then my GPU fans stuck and wont work, and also cannot support shader 3.0 when i tried to play devil may cry 4. so i changed into 9400gt 512ram 128 bit. i manage to play DMC 4 with medium setting, and all previous game at high settings. but after certain months, all my games eg GH 3, Most Wanted, keep getting slower overtime..and sometimes, even when i only started playing, it lagged. sometimes it went well but after sometime it lagged again.. then i tried playing Prototype, The last remnant, at medium and low settings, lagged and no different between high and low settings. so i thought maybe if i topup my CPU RAM and change a better GPU, it would be fine, so i change and upgrade my GPU and RAM.
at first, i tried playing the last remnant...for the first few minutes, in highest settings except shadow, the game is really smooth,seriously.but after a few loadings and all that, the game started to lag.same things happen with GH 3, and prototype. i tried lowering the graphic settings but the result is the same as if the setting dont affect anything..until now even when i reformatted my cpu, defragmented all my HDD, install latest vga drivers.still produce the same result..
i thought at first maybe because my GPU bit is 128bit with 9400gt, so i changed to 9600gt with 256bit.but result is nothing better.
but when i play DMC 4, it all went well.smooth at highest settings. thats why i've been soooo confused rite now...

3) hrm i think...
the problem occured when i changed my power supply..
because before this, when i newly changed my GPU to 9400gt from radeon,
it all went well until my PSU broke,the fan wont move,so i changed into a new one..
maybe...maybe this is my problem..
i dunno...
plzz...
any idea?
my PSU says at its body

AC230V 50hz / 4A and for DC OUTPUT for +12V : 18A

my GPU requires 400W with 12V current rating of 26A minimum

so plzz...is this the problem???
i'm really a noob
September 14, 2009 1:21:29 AM

>_>

Make a new thread, don't bring old ones back from the grave.
September 14, 2009 1:25:51 AM

ShtBrix said:
>_>

Make a new thread, don't bring old ones back from the grave.



i did...
plzz...see
Forum > CPU & Components > Power Supplies, PC Cases & Case Mods > I dont know but my pc games keep getting slower!!! plzzz help me...
September 14, 2009 1:26:53 AM

Then why did you necro this one?
September 14, 2009 1:33:49 AM

ShtBrix said:
Then why did you necro this one?



i hope u guys can help me...
becoz this guy here had almost the same problem as i do...
September 18, 2009 8:01:09 AM

cruelred88 said:
hye guys...
plzz i need your help,
i'm currently using a cpu and these are my specs : these WERE my cpu specs before :

intel D945PLRN motherboard same motherboard
ram 2gb 512 mb ram
intel dual core 2.66ghz same
nvidia geforce 9600 gt 512 ddr3 256bit ati radeon ( forgot the model) 256 ram ddr2
240gb HDD same
windows XP SP2 system same

before this, i've been playing a lot of games include prince of persia, devil may cry, dynasty warrior, PES, NFS ( from MOst wanted to carbon ) and evrything went well without any lagging...using my old graphic card. then i tried to play DMC 4, at that time my ATI couldnt support, so i chose 9400gt. it went quite well except it is lag..i know that game in high graphic..
then i bought the last remnant, still lag.so i chose a new one 9600gt.
i thought by changing the graphic card, i would have no prob with lag anymore.but i was wrong.
the games i played, kept getting slower...earlier in the game all is smooth and fun to play..but after a few minutes, it lag again...
and now even games with low graphic is slow...even PES, most wanted, guitar hero. while before i change into 9400 n 9600gt, this game is really smooth.
even at highest graphic setting in 9400gt.
now there are no difference wheter in lowest or highest settings.

1) so some one plzz help me..
i wanna know why..
is it my processor?
because the utilities sofware i installed says that my processor temperature is above limit.but my computer doesnt shut down by itself while playing games.
plzzz

2) ok let me explain a bit detail...
before this i've been using ATI radeon GPU which last for more than a year.
using this GPU, i've been playing guitar hero 3 at medium settings, most wanted, carbon, DMC 3, dynasty warriors, pro evolution soccer, with no lag at all.
but most of them at medium or almost high graphic settings. then my GPU fans stuck and wont work, and also cannot support shader 3.0 when i tried to play devil may cry 4. so i changed into 9400gt 512ram 128 bit. i manage to play DMC 4 with medium setting, and all previous game at high settings. but after certain months, all my games eg GH 3, Most Wanted, keep getting slower overtime..and sometimes, even when i only started playing, it lagged. sometimes it went well but after sometime it lagged again.. then i tried playing Prototype, The last remnant, at medium and low settings, lagged and no different between high and low settings. so i thought maybe if i topup my CPU RAM and change a better GPU, it would be fine, so i change and upgrade my GPU and RAM.
at first, i tried playing the last remnant...for the first few minutes, in highest settings except shadow, the game is really smooth,seriously.but after a few loadings and all that, the game started to lag.same things happen with GH 3, and prototype. i tried lowering the graphic settings but the result is the same as if the setting dont affect anything..until now even when i reformatted my cpu, defragmented all my HDD, install latest vga drivers.still produce the same result..
i thought at first maybe because my GPU bit is 128bit with 9400gt, so i changed to 9600gt with 256bit.but result is nothing better.
but when i play DMC 4, it all went well.smooth at highest settings. thats why i've been soooo confused rite now...

3) hrm i think...
the problem occured when i changed my power supply..
because before this, when i newly changed my GPU to 9400gt from radeon,
it all went well until my PSU broke,the fan wont move,so i changed into a new one..
maybe...maybe this is my problem..
i dunno...
plzz...
any idea?
my PSU says at its body

AC230V 50hz / 4A and for DC OUTPUT for +12V : 18A

my GPU requires 400W with 12V current rating of 26A minimum

so plzz...is this the problem???
i'm really a noob




---------------------------------

Hie Even i did face the same problem i thought this post was posted by me earlier!!!
Starting Prototype has some serious issues regarding performance try googling protoype sound issue
second i had also replaced 9400gt to other graphic card but still the performance didnt change.I think ur processor is overheating plz change the thermal interface material u can get from electronics shop
i did remove the processor and then again plug in and the performance was almost 8x


i think you should try:
1.i think you ram is of 533 or 400mhz so replace it with other ram with higher mhz dont i think 667 might work and dont worry about still higher mhz because they work but at low frequency
2 it thnk that the 512 ram should be of low mhz so it far better to remove the 512 mb ram and keep 2 gb ram only
3.did u plug fans extra fans.because they may consume a lot of power and the performance may degrade
4.dont thing dual core is the problem.
5.there is issue with the dual core processor instead of 2mb or 4mb cache the bios shows just 1 mb ram so to fix do bios upgrade
September 18, 2009 9:59:36 AM

kdhallu said:
---------------------------------

Hie Even i did face the same problem i thought this post was posted by me earlier!!!
Starting Prototype has some serious issues regarding performance try googling protoype sound issue
second i had also replaced 9400gt to other graphic card but still the performance didnt change.I think ur processor is overheating plz change the thermal interface material u can get from electronics shop
i did remove the processor and then again plug in and the performance was almost 8x


i think you should try:
1.i think you ram is of 533 or 400mhz so replace it with other ram with higher mhz dont i think 667 might work and dont worry about still higher mhz because they work but at low frequency
2 it thnk that the 512 ram should be of low mhz so it far better to remove the 512 mb ram and keep 2 gb ram only
3.did u plug fans extra fans.because they may consume a lot of power and the performance may degrade
4.dont thing dual core is the problem.
5.there is issue with the dual core processor instead of 2mb or 4mb cache the bios shows just 1 mb ram so to fix do bios upgrade


Create a new damn thread! Most likely no one would respond to this one.
October 7, 2009 10:56:32 PM

pogsnet said:
To me a big YES! system would crash or cause error if not correct voltage is given to your PC. You can check that at BIOS.

12V = should be 12v or 12.2 not 13v, most cheap PSU is under 12v
5v = 5v or more but should not reach 5.5v not 4.8v (some PSU does)
3.3v = 3.3 or more but not reach 4v
This affect games...usually heavy games will crash. Even Warcraft DOTA, errors will appear based on my experience as I changed my PSU this problems was avoided already.

@Crashman
lol 42037 posts already.... You should be called man of the ancients. [:pogsnet]


My 3.3V = 3.26V under load with 29% overclock. The others are fine. My +12V on the Power Supply is 18A. 430W PSU.
When I increase my FSB by one or more it doesn't work. When I try to increase Vcore it does not make it stable even with mem at 1:1.
Stable at 429FSB from 1.21V - max but not stable on 430FSB or higher.

Is it my Power Supply or something else?
!