UNSOLVED
7800 gtx 512mb power supply
Hi,
I dont understand why BF2 runs so jumpy and with not particualry impressive fps... From like 70fps down to 50 fps and i see 40 fps too.
1280x1024, x4aa + x8af
I've tried loads of nvidia drivers... [I have a 2mb bt yahoo adsl connection]
That may look alright, but the actual gameplay just isnt smooth, feels jumpy and chuggy.
I think a possible weakness could be my power supply?
http://cgi.ebay.com/Dell-NEW-NPS-46...bayphotohosting
Its a Dell 460W PSU
two 12V rails rated at 18.5 amps? [from wot i can see]
I dont understand why BF2 runs so jumpy and with not particualry impressive fps... From like 70fps down to 50 fps and i see 40 fps too.
1280x1024, x4aa + x8af
I've tried loads of nvidia drivers... [I have a 2mb bt yahoo adsl connection]
That may look alright, but the actual gameplay just isnt smooth, feels jumpy and chuggy.
I think a possible weakness could be my power supply?
http://cgi.ebay.com/Dell-NEW-NPS-46...bayphotohosting
Its a Dell 460W PSU
two 12V rails rated at 18.5 amps? [from wot i can see]
- the answer is yes, the weakness is the Gen 3 psu. The 512mb GTX is a power hog. I tried my GTX on the Gen 4 and didn't last long then I placed it on my AMD rig with a psu of 600w. Whew...no sweat there...Search to see if you can get an upgrade of at least 550w to match that bad boy's power thirst...
- I just did the step-up with eVGA for a 7800GTX 512mb card, and now reading this thread, I am a little nervous. I am wondering... audiopho was your's an overclocked version like lewis-1's. The reason I ask is that the web sites for BFG and XFX listing the overclocked versions state that 26a is needed but for the standard 550mhz card this is not mentioned. Also was wondering if it was the 550mhz one, did you try under-clocking it a little.
I am just hoping I didn't waste my time and $$$ on a card I can't power.:smileysurprised: - your power supply limits you to 34A (about 400W) max combined on the 12V rails (A+B). You probably wouldn't want to exceed about 320W (about 80%) that has to be shared with all the items on the 12V rail such as processor, drives, fans AND PCI Express graphic card(s). And then your power supply has to also handle the 3.3 and 5V rails, and the stuff on them like motherboard, ram, usb, etc.
- ATX12V standards have limited the max on a single 12V rail to about 18A or so for stable voltage, so to increase the total amps on the 12V rail, they increase the number of rails within the power supply. For example, the Dell 460W has 2 - 12V rails, the 650W has 3 -12V rails, each rated about 17-18A... you can't actually distrubute the load as it's all controlled within the power supply unit. Specs are changing now though with the high output (up to 1KW now) power supplies that meet server type power supply standards.
I and another forum mate had posted a question to Dell mod about the psu spec for all Gen3,4, and 5. Still haven't heard from...typical from Dell Tech support, I supposed.
Mine is 256mb version. Lewis's is a 512mb and it is a monster when it comes to power thirst. A typical current requirement for this card is at least 36-40a from both +12v rails if you were to ask eVGA tech support in which I did. My Gen4 was barely able to sustain the card at 3d apps. At times, I do get a warning from Nvidia driver for low voltage detected from the gpu itself. That's why I yanked the gtx out of my Gen 4 and placed it in my AMD for good. As for benchmark, the Gen 4 managed to squeeze a very low 7100 points on 3dmark05, and the AMD just simpy smokes the Gen 4 by a score of 8400.
Have you yet started seeing the picture by looking at the benchmark scores between two systems? The difference is the pus of the where the AMD is 550w and the dell is 450w. It's no brainer that the psu plays a key role of how high a g/c can push.
Message Edited by audiopho on 03-08-2006 08:38 AM
Now if I can just figure out how to pay for this thing and how to hook this thing up without making my computer look like a Borg ship I will be all set. :smileyvery-happy:
http://www.pcpowercooling.com/products/viewproduct.php?show=TC1KW&view=about
- I have not received my 7800GTX 512 yet but just out of curiosity I called Dell spare parts to see how much the 650w PSU that comes with the XPS 600 would be. (it's $190 if anyone is interested) They said that I could not use the 650w in my Gen 4 because it would fry my motherboard???? This does not make sense to me or the nice folks I called @ eVGA. I have added many higher wattage PSU's to Dell systems w/o any problems. Anyone have any thoughts on this???
lewis_1
103 Posts
534
0
Posted February 24th, 2006 19:00
minimum:
450W PSU with (12 V rail of 26A)
So does my psu only have 18.5A on the 12V rail? or is it two 18.5A combined?
Hence, i need a psu with the 12 V rails rated @ 26A each????