What happens if pc is underpowered

[robertg231]

So i am going to get a new gpu but it require a minimum psu of 400 watts
i only have 375 watts. would this work or would it harm my system

 

[k1114]

The recommended watts is always higher than what it needs to cover bad quality psus. If that 375w psu is good quality than you should have no problems.

If it's the 4350 in you other posts than that's well below the 400w requirement. It's only a max of ~18w.

 

[robertg231]

its not the 4350. i want to use a hd 4670

 

[HEXiT]

what exactly are the system specs...
running close to max will cause heat, random shut downs, and possible damage to other parts of the system. just because your systems psu is rated at 375 watts doesnt mean you have 375 to use. that may be the peak output and may not be stable. resulting in powerspikes and other potentialy harmfull issues.

if its a new build i wouldnt risk it.

 

[jaguarskx]

The HD 4670 will be able to run on an average 375w PSU assuming you do not have many components that draws a lot of power like having 8 hard drives and an overclocked Core i7-2600K CPU.

It's best to list your components and precisely which 375w PSU you have.

If you have the $$$ for a Radeon HD 5670 (which is probably around $60 - $70 after rebates), then that would be a better choice since it uses less power than the HD 4670 and is also gives on average around 25% - 30% better performance in games.

 

[robertg231]

what specs do u need

 

[photonboy]

**READ THIS**

It is not the "Wattage" you need to pay the most attention to. It is the Amps that it can supply on the 12V rail (or rails).

For example, a high-end card like the GTX570 requires 38A (amps). There are some 500 Watt supplies that can manage this, but most that won't.

The information is either on the PSU, your manual, or the manufacturer's website.

 

[photonboy]

There are programs on the Internet that allow you to input all your computer details and they tell you the WATTAGE you need. Some programs are more up to date and/or better than others.

To be clear, you should know:
1) the approximate Wattage that you need
2) the Amps you need for your graphics card (get at least 25% better than your graphics card rating. For example if the card needs 10A, then 10x1.25 is 12.5Amps minimum on the single or combined +12V rail/rails.
3) connection types, such as 6-pin or 8-pin which are on the graphics card but which might not be on the PSU.