additional power supply

[sal_rc]

I have a cheap 450 watt Psu and I think it's bottlenecking
My CPU is Amd phenom II x4 955be and GPU is gtx750ti.
So my question is how can I use additional power supply to power my 750 ti.I have an old 300 watt psu.
Can I only use its 4 pin plugs to power my GPU?

 

[Mattios]

Your PSU does not bottleneck. If the components draw too much power it will cut off, thats it. There is no inbetween.

 

[geofelt]

A GTX750ti uses 75w from the motherboard X16 slot.
You have more than enough.

If your fps performance is not adequate, here is my stock answer:
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To help clarify your CPU/GPU options, run these two tests:

a) Run your games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.

b) Limit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 70%.
Go to control panel/power options/change plan settings/change advanced power settings/processor power management/maximum processor state/
This will simulate what a lack of cpu power will do.
Conversely what a 30% improvement in core speed might do.

You could also experiment with removing one core. You can do this in the windows msconfig boot advanced options option. set the number of processors to less than you have.
This will tell you how sensitive your games are to the benefits of many cores.

If your FPS drops significantly, it is an indicator that your cpu is the limiting factor, and a cpu upgrade is in order.

It is possible that both tests are positive, indicating that you have a well balanced system, and both cpu and gpu need to be upgraded to get better gaming FPS.
-------------------------------------------------------------

 

[sal_rc]

@mattios @geofelt
The thing is whenever GPU is under load I hear some kinda noise from PSU, like some sparking or buzzing noise.
And about my CPU I don't think its the limiting factor cuz during gaming only 50-60% cpu is used.
What I am worried about is noise,
And I have gigabyte 750 ti which uses a six pin connector and my PSU don't have one so I'm using 2 four pins and I'm still short of one for my DVD ROM, so I wanted to know if I can use my old PSU to power either of the one

 

[geofelt]

Exactly what make/model is your psu?
Sparking sounds alarming.
A cheap psu may not deliver advertised power and the fan will spin up under load.
The real danger is that it will not have the protective circuitry to protect your parts if it fails under load.
If you need to use a molex to 6 pin adapter, it is likely your psu is substandard or it would have had such a connector.
Really, adding a second cheap 300w psu is no solution and can be complicated.
You need to find a mechanism to power on the second psu; the switch alone will not do it.
Buy a quality replacement psu. Look for Seasonic, antec, xfx. with at least a 6 pin power lead, most likely 400w.

 

[sal_rc]

@geofelt my current one is zebronics,its a domestic manufacturer I think and it's not exactly sparking noise but yeah
And about the old 300w PSU,its bestec that came with my original Compaq
Should I try the bestec?if 300 watt isn't enough it won't power up,right?

 

[geofelt]

I would dump them both asap in favor of a quality psu.
Zebonics is tier 5 on this list, and I think bestec is no better
https://community.newegg.com/eggxpert/computer_hardware/f/135081/t/45344.aspx?Redirected=true
A cheap PSU will be made of substandard components. It will not have safety and overload protections.
If it fails, it can destroy anything it is connected to.
It will deliver advertised power only at room temperatures, not at higher temperatures found when installed in a case.
The wattage will be delivered on the 3 and 5v rails, not on the 12v rails where modern parts
like the CPU and Graphics cards need it. What power is delivered may fluctuate and cause instability
issues that are hard to diagnose.
The fan will need to spin up higher to cool it, making it noisy.
A cheap PSU can become very expensive. Do not use one.

 

[sal_rc]

Thanks for the help, I'll try to replace asap