General discussion

350Watt Graphic Card in 300W Power supply ?

I recently upgraded to XFX Nvidia Geforce 8400GS. The XFX Recommended Power supply requirements written on the cover box is 350 Watts, But the power supply of my PC is 300 Watts. The graphic has been correctly recognised by my motherboard and it's working OK.
Also ever since i've installed the Geforce 8400GS card, the IEEE 1394 Adaptor(FireWire) component has been disappeared from the Network Connections.
Will there be any performance drop in the graphic card, will this card damage the motherboard or any other PC components and why did the IEEE 1394 disappear ?

Graphic Card :- XFX Geforce 8400GS 256MB ON BOARD SUPPORTING 512MB DDR2 (Model-PV-T86S-WAQG)

PC config:
Intel 945G Chipset
Intel Pentium 4 3.06Ghz HT
2 GB DDR2-533 Dual-Channel Ram
80 GB Hard Disk
Windows XP Home

Discussion is locked
Reply to: 350Watt Graphic Card in 300W Power supply ?
PLEASE NOTE: Do not post advertisements, offensive materials, profanity, or personal attacks. Please remember to be considerate of other members. If you are new to the CNET Forums, please read our CNET Forums FAQ. All submitted content is subject to our Terms of Use.
Reporting: 350Watt Graphic Card in 300W Power supply ?
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
- Collapse -
Since I have a 3.0 GHz HT in the lot...

My answer is NO, DON'T DO THAT.

Overtaxing a power supply is shaky ground and at least here not very expensive to fix. See those 500+ Watt PSUs at I use the 680W units since there is no need to go lower and the PC will use what it needs so the extra is just headroom. We want a lot.


- Collapse -
Is my motherboard being damaged by using 300W PSU ?

So, usage of my PC till now would have been started damaging my motherboard and other PC components ?

- Collapse -
Yes it can be. Here's why.

The power supply supplies... power. If you push it then a few things can happen. Unless you get out an oscilloscope you can't see this going on.

1. The motherboard and other capacitors work harder.

The power supply can have more ripple on it since you are at or over it's capacity. The other capacitors on motherboard and other place now get more ripple and age faster.

2. If the power fails it's unclear what happens next.

I've had power supplies (overloaded ones) that just refuse to start one day. Some owners have had them self destruct and when they did the motherboard and cards receive a spike or over voltage and the machine's contents (even hard disks) have been lost. Since the power supply is some 20 bucks these people were not happy at losing the entire machine over such a cheap part.

This is all your choice. It is not something I'll do.


- Collapse -
Can the motherboard be saved ?

So after the installation Of new PSU ,will the motherboard work fine as it was before, or has the motherboard been started being damaged which cannot be recovered ?

- Collapse -
Is it lost?

All I noted was the aging. Please tell me what was damaged?


- Collapse -
No,i meant.....

No, I mean , will the performance of the motherboard and the other PC components be dropped from Before ?

- Collapse -
You would have to tell us.

Sorry but I'm missing what the question is. Only you can tell us if you have noticed a performance issue.


- Collapse -
(NT) ok, plz can u give me the ans of post no.11 ?
- Collapse -
(NT) sorry, not the post no.11 but the ans of post no.13
- Collapse -
sorry sorry sorry !

the post nos are changing, so i want to know about the compatibility of a PSU

- Collapse -
Get a new psu

Run, don't walk and get a larger and decent name compatible PSU. While, it may be running now it will sooner or later be kaput.

As for the 1394 not working, be sure to recheck your work on the video install and didn't upset any other cabling or harness for 1394 operation and/or the bios shows it enabled. If need be, re-install the driver.

tada -----Willy Happy

- Collapse -
Installation of new PSU ?

But, Is it difficult to remove the Old PSU and installing and wiring of the new PSU ? Can i do it myself without the help of a mechanic ?
Also which Brands of PSU should i prefer ? And how much would they cost ?

- Collapse -
A video with the power supply being changed.
- Collapse -
Compatibility of PSU ?

What all things should be considered for the Compatibility of a PSU ?

- Collapse -
Plz answer my ques .

Please someone answer the questons in Post no.7 and no.11

- Collapse -
Number 7 is

Not unlike you asking me about the performance of your car before and after you put gas into it. I can't answer this. Please rewrite the question.

The machine and power supply you describe so far sounds just like the standard ATX power supply you find in 99% of the machines out there. Once in awhile people microanalyse such things but it's very simple.

Measure the size of the power supply and compare it to the new one. There is huge leeway on the ATX form some I've seen some not be able to install a power supply because their measurements were off by an 1/8 inch. For those I'll just do the change for them and button it up. One person still complained and we had to uninstall the (working) power supply and send them on their way.

Don't get too exact on those measurements and look for documentations such as and for ATX DIMENSIONS.

This is not tech support but people trying to help you help yourself...


- Collapse -
Not hard...

A decent PSU will cost abit, but fall for truly cheapo ones. I just brought a Logisys 575W at for $40, not to include s/h fee. There are those out there in the $25 or less range, but don't count on them. More pricey ones will be expensive but they do deliver the goods. Also, be sure to buy that will fit and meet the physical limits of your case. If you have a std. generic case, you'll do fine. if you have a Dell or similar be sure to ask if it will fit. Now, to install is pretty much a straight-forward install, take notes if you like but overall its easy.

Check and for psu pricing or any other source.

tada -----Willy Happy

- Collapse -
That Logisys. I think I picked up the 500 Watt last year.

It was quieter than most and I like that the swiss cheese full of holes effect on the back grill to get the heat out.

Those 680Watt units for cheap are as you suspect not going to have me testing if they can do the full load but I must have a dozen between home and office and uncounted numbers that I used on repair jobs. Not one man down yet.


- Collapse -
(NT) Yes, quiet all around
- Collapse -
PSU for Lenovo Desktop ?

I have a Lenovo 3000 Q series 8822 11Q Desktop And an XFX geforce 8400GS Graphic card installed, so which PSU should i buy ? of which Dimensions ?

- Collapse -
My 350w video card

I'm also planning on getting a 150w video card and using it with a 300w power supply. I also am buying a stick of ram as well. I don't have enough to get a new power supply but am planning on buying one a month or so after getting the card.

Could I get away with this?

- Collapse -
No one can answer this.

We can't know if your power supply will fail under the higher load. However some power supplies can take out an entire machine as they fail which is why I never push my luck.

You are more than welcome to try.


CNET Forums