Underclocking GPU to help weak PSU ?

[Jonathan Laliberte]

Hello, I just built back a PC with spare parts I had laying around in my closet and I have one problem. It's working great, windows 7 installed, but the Wattage consuption of the PC is 467W and I have only a 430W PSU. I want to use this computer only for 2d desktop ends so i wanted to know if I can decrease the consuption of my GPU to lower the Watt stress on my PSU. Thanks for all help and information.

This is the hardware:
PSU: Thermaltake TR2-430 (430W)
Motherboard : M4A78 Plus
CPU: AMD Athlon II X4 630
GPU: AMD Radeon HD 4890 1Gb (this is the hungry fellow)
RAM: 4 x 1Gb Kingston HyperX DDR3
Storage: HDD 500Gb Green Western Digital

I still got a Nvidia 7800 laying around I could use if that is the best solution!

 

[ragnar-gd]

Of course, the NV 7800 uses less power, but still...
It is, with your machine, i don't see that your machine uses more than 250 W (if at all) in idle or low usage 2d.
How do you measure power usage?

 

[Jamie_69]

https://images.anandtech.com/graphs/radeonhd4890_040209033751/18769.png

Total system power consumption in this review is under 300 watts with an i7 965. You won't need to reduce usage, but if you still want to you can always try MSI afterburner or EVGA precisionx. They should let you reduce the clocks.

 

[Jonathan Laliberte]

Of course, the NV 7800 uses less power, but still...
It is, with your machine, i don't see that your machine uses more than 250 W (if at all) in idle or low usage 2d.
How do you measure power usage?

Yeah I guess I won't need to change anything, Thx. I had calculated it with a PSU rig calculator and it said 467W, but now I did the same with http://www.coolermaster.com/power-supply-calculator/ and with the CPU full load it is 416W. (GPU clock reduction didnt change anything, I had forgot the consumption is equivalent to it's usage). But still, the recommended PSU for this rig is 500W even by coolermaster. I won't play consuming game with this so the thermaltake 430W should do the trick. This is obviously not my gaming rig btw

 

[ragnar-gd]

I own a watt-meter for checking the power usage of devices at home. It is a nice thing to have, so you might consider owning one:
https://www.amazon.co.uk/Voltage-Electricity-Monitor-Analyzer-Digital/dp/B071NZ53WR/ref=sr_1_1_sspa?ie=UTF8&qid=1522427299&sr=8-1-spons&keywords=watt-meter&psc=1
(Just an example, i don't recommend one over the other)

 

[geofelt]

4890 typically needs two 6 pin connectors which your 430w psu likely does not have.
Using adapters is not recommended.

Power usage increases when gaming so it is possible that for desktop use your plan will work.
Since you have the parts, you have the means to try and see how it does.
If a graphics card does not have sufficient power, the first symptoms will be display artifacts.
That, you can handle.
A potentially more serious problem is the quality of the PSU. Thermaltake TR2 is not a great quality unit and may not deliver advertised power.
Worse, if it fails under load, you can damage other parts.

It would probably be better to buy a used cheap low power graphics card on ebay to do the job.

 

[Jonathan Laliberte]

4890 typically needs two 6 pin connectors which your 430w psu likely does not have.
Using adapters is not recommended.

Power usage increases when gaming so it is possible that for desktop use your plan will work.
Since you have the parts, you have the means to try and see how it does.
If a graphics card does not have sufficient power, the first symptoms will be display artifacts.
That, you can handle.
A potentially more serious problem is the quality of the PSU. Thermaltake TR2 is not a great quality unit and may not deliver advertised power.
Worse, if it fails under load, you can damage other parts.

It would probably be better to buy a used cheap low power graphics card on ebay to do the job.

yeah, I turned 2 molex into one 6pin, I am gonna try some games as test and if I get shutdowns or artiefacts I am gonna either switch to the 7800 (which is fucking old) or buy a slightly better PSU. Should any 500W do the trick or a bad one could be worst?

 

[geofelt]

DO NOT buy a cheap psu.
A cheap PSU will be made of substandard components. It will not have safety and overload protections.
If it fails under load, 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 buy one.

I like the new Seasonic focus line. Even the 450w version has two 6 + 2 pcie connectors.
https://www.newegg.com/Product/Product.aspx?item=N82E16817151204