PSU question
Armageddon
Join Date: 2005-01-07 Member: 33055Members
Join Date: 2005-01-07 Member: 33055Members
<div class="IPBDescription">and graphics cards</div>Hello my fellow gamers,
I recently purchased a new graphics card (ATI Radeon x1950gt 256mb AGP) and it says that one of the minimum requriements is that I have a 450W PSU capable of delivering 30 amps on the 12v rail. Unfortunately, my PSU only delivers 25 amps so I'm 5 short. Would this cause my card to underperform in terms of framerate during gameplay (assuming I have everything on low)? The reason I'm asking is that I was all excited and everything on Monday to have gotten this new card to replace my old ATI Radeon 9000 but I was disappointed when I discovered I couldn't play HL2 at 100 fps on high or low settings like the reviews at newegg said (i get like 50).
Thanks,
a fellow gamer
p.s. I have a P4 2.66 GHz CPU, 1 GB ddr ram.
I recently purchased a new graphics card (ATI Radeon x1950gt 256mb AGP) and it says that one of the minimum requriements is that I have a 450W PSU capable of delivering 30 amps on the 12v rail. Unfortunately, my PSU only delivers 25 amps so I'm 5 short. Would this cause my card to underperform in terms of framerate during gameplay (assuming I have everything on low)? The reason I'm asking is that I was all excited and everything on Monday to have gotten this new card to replace my old ATI Radeon 9000 but I was disappointed when I discovered I couldn't play HL2 at 100 fps on high or low settings like the reviews at newegg said (i get like 50).
Thanks,
a fellow gamer
p.s. I have a P4 2.66 GHz CPU, 1 GB ddr ram.
Comments
Hello my fellow gamers,
I recently purchased a new graphics card (ATI Radeon x1950gt 256mb AGP) and it says that one of the minimum requriements is that I have a 450W PSU capable of delivering 30 amps on the 12v rail. Unfortunately, my PSU only delivers 25 amps so I'm 5 short. Would this cause my card to underperform in terms of framerate during gameplay (assuming I have everything on low)?<!--QuoteEnd--></div><!--QuoteEEnd-->
Not unless your PSU goes to sillicon heaven. There's a fair bit of margin in those specs, but blowing a PSU is not that terribly fun and in rare cases it might take another component with it.
<!--quoteo(post=1641803:date=Aug 2 2007, 03:57 PM:name=TychoCelchuuu)--><div class='quotetop'>QUOTE(TychoCelchuuu @ Aug 2 2007, 03:57 PM) [snapback]1641803[/snapback]</div><div class='quotemain'><!--quotec-->I've never done this or anything, but I'm thinking it'll either throttle down or just start crashing when it tries to draw more power than it can. If your FPS isn't so hot, I'm thinking it just isn't running as fast as it could. Upgrade your PSU, I guess.<!--QuoteEnd--></div><!--QuoteEEnd-->
I'm pretty sure that's only CPU's and only due to heat. It'll probably just crash if it's getting fed too poor voltages.
That's what I figured too, but he mentioned that he's getting lower FPS than he expected, so unless he's got a second problem that might be what's going on.
<!--QuoteEnd--></div><!--QuoteEEnd-->
He should try bumping the res to native and see if performance takes a big dip. If it doesn't he's very CPU bound.
HL2 always was a bit of CPU hog(http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2330&p=2 , in one place it apparently struggles to reach 50 FPS on a better CPU than he has).
It's a fair bet that a P4 2.66 GHz refers to a northwood B with 133 MHz FSB(quad pumped. Uses 266 MHz DDR modules in dual channel mode). HL2 is quite sensitive to memory bandwidth and latency, and so is the P4 architecture.
It's probably also a good idea to run 3dmark06 or some benchmark app and compare his scores on GPU benchmarks against other people.(this will also help determine if his PSU is up to the task. If it goes flakey under load and he crashes he should probably not run any demanding apps before replacing it)
blah blah techno-jargon
<!--QuoteEnd--></div><!--QuoteEEnd-->
how's that for Swedish efficiency. <img src="style_emoticons/<#EMO_DIR#>/wink-fix.gif" style="vertical-align:middle" emoid=";)" border="0" alt="wink-fix.gif" />
<!--quoteo--><div class='quotetop'>QUOTE</div><div class='quotemain'><!--quotec-->I've never done this or anything, but I'm thinking it'll either throttle down or just start crashing when it tries to draw more power than it can. If your FPS isn't so hot, I'm thinking it just isn't running as fast as it could. Upgrade your PSU, I guess.<!--QuoteEnd--></div><!--QuoteEEnd-->
Yeah I was thinking the same thing. I have a 500 watt PSU with 34A on the 12V rail but I can't fit it into my computer case <img src="style_emoticons/<#EMO_DIR#>/sad-fix.gif" style="vertical-align:middle" emoid=":(" border="0" alt="sad-fix.gif" />
<!--quoteo--><div class='quotetop'>QUOTE</div><div class='quotemain'><!--quotec-->HL2 always was a bit of CPU hog(http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2330&p=2 , in one place it apparently struggles to reach 50 FPS on a better CPU than he has). <!--QuoteEnd--></div><!--QuoteEEnd-->
-_-
Oh, I forgot to mention that I'm also having low framerate issues with another game (Rappelz). I posted an issue regarding my new graphics card up on their tech support forums and I was told by someone who had an ATI Radeon 1600XT (a card which, if I'm not mistaken, is older and not as good as mine <img src="style_emoticons/<#EMO_DIR#>/tounge.gif" style="vertical-align:middle" emoid=":p" border="0" alt="tounge.gif" />) and system specs lower than mine that he was able to run the game on high with no problems at all :\ My instinct tells me that it is the PSU but I can't be too sure as I'm a novice with computer parts.
Before I forget, my PSU is 580 W with 25A on the 12V rail. It's "recommended" that the card run on 30A on the 12V rail.
and system specs lower than mine that he was able to run the game on high with no problems at all :\ My instinct tells me that it is the PSU but I can't be too sure as I'm a novice with computer parts.<!--QuoteEnd--></div><!--QuoteEEnd-->
What CPU does he have? A common novice mistake(at least in the past) was the assumption that clock frequency is all that matters. A 1.8 Ghz athlon 64 with single channel DDR400 will be significantly faster than your CPU in most games.
u equals r times i
Or in other words:
12V equals (cards resistance) times 30A
-> R=I/U
So your card is supposed to have a resistance around 2.5 OHM.
If you run it with only 25A then we get:
2.083OHM (That the card needed to operate at its optimum under 25A)
1-2.083/2.5
And we can see that you are around 17% short in therms of expected resistance.
This means, that your card will at least underperform by 17%!!!
It wont fry cause in order to fry you would need to put more juice through it than it needs. Instead you put less juice through it causing it to underperform.
post scriptum:
or we just cut the crap and see the following: card resistance = constant, voltage = constant, 25/30 =0.83 results in 17% underperformance
That's terribly wrong for a myriad of reasons. The most obvious being that CMOS does not get work done by producing heat, it gets work done by switching logical gates in response to a clock signal. This clock signal will not change in frequency if you fail to supply enough power to the card unless there is a dedicated circuitry for doing so. What will happen when you fail to supply enough power to the card is that some transistors in RAM chips or the GPU will fail to switch as expected. This will result in various forms of corruption such as random polygons or artifacts on your screen or it may kick the GPU into some undefined state from which it can't recover normal operation and become unresponsive to the system driver(I.e. a crash).
2 ghz p4, 1gb ddr ram
2 ghz p4, 1gb ddr ram<!--QuoteEnd--></div><!--QuoteEEnd-->
Hmm.
Have you checked to see that you <i>really</i> are GPU bound? If the GPU is indeed a bottleneck the framerate should dip significantly if you increase resolution or add some anti-aliasing.
Going to try some very newbie mistakes, don't take offense:
The card should have a separate power connector(typically a female PCI-E power connector) on the card itself, because the motherboard cannot supply enough power through the AGP slot alone to run the card. If you forgot to plug this in or it somehow got loose while closing the chassis the most likely result is that the PC won't boot at all and will just generate a series of internal speaker beeps. It's possible that newer cards could sense this and have a 'safety mode' where it runs at much lower clocks to avoid killing your motherboard.
Did you forget to uninstall the old drivers and grab some new ones from ATi/AMD's site?
And yes I have the latest drivers (CAtalyst 7.7) although I read on the Newegg website reviews that catalyst 7.5 gives higher performance in HL2. I tried catalyst 7.5 today and I see no difference.
<img src="style_emoticons/<#EMO_DIR#>/sad-fix.gif" style="vertical-align:middle" emoid=":(" border="0" alt="sad-fix.gif" />
<a href="http://www.newegg.com/Product/Product.aspx?Item=N82E16814102093&Tpk=ati%2bradeon%2bx1950gt%2bagp" target="_blank">http://www.newegg.com/Product/Product.aspx...2bx1950gt%2bagp</a>
I was playing HL2:Deathmath earlier today on 1024x768 on default settings and I experienced a lot of framerate dips during firefights. I have everything in the ATI Catalyst driver set to minimum (no AA, V-sync, Antiscopic filtering, etc.. everything to the lowest possible).
This is the card I brought:
<a href="http://www.newegg.com/Product/Product.aspx?Item=N82E16814102093&Tpk=ati%2bradeon%2bx1950gt%2bagp" target="_blank">http://www.newegg.com/Product/Product.aspx...2bx1950gt%2bagp</a>
I was playing HL2:Deathmath earlier today on 1024x768 on default settings and I experienced a lot of framerate dips during firefights. I have everything in the ATI Catalyst driver set to minimum (no AA, V-sync, Antiscopic filtering, etc.. everything to the lowest possible).
<!--QuoteEnd--></div><!--QuoteEEnd-->
IRQ conflict perhaps? The AGP slot and the PCI slot immediately below it share an IRQ on many motherboards, you don't want to stick other busy components like a sound card or NIC there.
You might want to have a look at newer bios versions for your motherboard and see if any of them specifically mentions any issues with newer AGP cards.(it is always slightly risky to upgrade BIOS, if you don't find a reason to suspect it is an issue, don't)
It still does not sound like a graphics performance issue; your graphics card does not really care much if you are fighting or admiring the scenery. Please test that your performance is REALLY bounded by graphics. Load up HL2 single player and check the framerate at some place reasonably strenous; now switch to native res and enable some ingame AA and AF for good measure. If your framerate stays almost the same that tells you that graphics performance is fine, but something else isn't.
I also realized that I never uninstalled the old video card drivers for my PCI card, so I think there's an issue there. I will get back when I find the time to fix everything up.
Ok I didn't know what an IRQ conflict was until you mentioned it. SO I did some googling and I found out how to check if my devices were in conflict. It turns out that my Card, which is on the AGP slot but is being read as PCI, shares the same channel as the "Standard Universal PCI to USB host controller" (PCI). Strange o.O I read that 2 devices using the same channel could cause problems as each device has its own channel to communicate with the microprocessor.<!--QuoteEnd--></div><!--QuoteEEnd-->
(AGP shares the same 33 MHz clock-signal as PCI and multiplies the frequency(AGP 1x is 66 MHz, AGP 2x is 133 and so on). Things like pci-latency are measured in PCI clocks(how long a single device may hog the bus before having to yield to other devices that might need to use it urgently.). The AGP slot and the PCI slot immediately below it often have the same IRQ number.)
An IRQ conflict with a USB host controller is unlikely to do much harm and it might not be fixable. You should try and avoid conflicts with more intesive stuff like 100 mbit ethernet cards, sound cards, PCI SATA raid controllers and stuff.
<!--quoteo(post=1642179:date=Aug 5 2007, 02:50 AM:name=Armageddon)--><div class='quotetop'>QUOTE(Armageddon @ Aug 5 2007, 02:50 AM) [snapback]1642179[/snapback]</div><div class='quotemain'><!--quotec-->I also realized that I never uninstalled the old video card drivers for my PCI card, so I think there's an issue there.<!--QuoteEnd--></div><!--QuoteEEnd-->
That seems much more likely to be the problem. Uninstall both drivers, reboot and reinstall one of the drivers of recent vintage.