Can insufficient PSU be a problem for GPU?

[rog02]

Hello Guys,

I purchased Sapphire HD6850 some days back.
It is working fine.
Problem is while playing games monitor screen flickers / fluctuates (like vibration waves).
But when I close the game, all works fine. Also while watching movies, there is no flicker on the monitor.

The system I am using is Dell Precision Workstation T3400.

I think this problem is due to my PSU which is 375W only.
When I play games, card might be asking for more power than idle state, that's why screen flickers
But not sure about it, so want opinion on what could be the reason.

NOTE: I am not facing problems of shutdown or freezing.

Any Idea?

 

[Novuake]

Yip, low power for sure. It cause serious issues if the PSU goes violently. Taking a board and GPU with in some cases.

 

[Dogsnake]

The AMD cards throttle their power requirements in step with GPU demand/load. So it is possible that during regular computer use and movie watch little demand is on the GPU. During games the GPU is utilized to a high degree and it's power draw increases dramatically. At idle that card draws about 130w under load about 230w. Since your PS is aged a bit you can figure it has modest decrease in capacity also. It is a pretty good bet that you are tapping the PS out when playing the games. You do need to replace the PS because if it fail under stress the protection circuits may no work correctly. You could end up with additional component damage. Not having a component list I can not be sure of a right size to recommend but a guess would be about 650w. Here is an example (http://www.newegg.com/Product/Product.aspx?Item=N82E16817207014). It does not have modular cables but is a good unit at a good price. You could probably do with a 600w if you wanted to save some cash. If you post more info we can do a rough calc. on what you need.

 

[RetiredChief]

A "High quality" psu could probably handle the 6850. Typical system using the 6850 is around 275 -> 300 Watts) Watts, Idle is much lower.

Most likely your Your Dell PSU is only of average quality. Personally I'd upgrade the PSU to 450 Watt corsair, or other good brand (ALWAYS look for reviews of PSU you are thinking of buying).One way to verify is to use a program to display your +12 V (I use HWMonitor) then download and run furmark (in window), monitor your +12 V, should NOT drop below +11.4 V (Spec, myself I use 11.6V as absolute min). NOTE if +12 v displayed in HWMonitor looks funky at Idle, it not reporting correctly so need to try different program, is speedfan.


@ DogSnake, a 650 W is overkill unless planing on Xfire two cards, But if he is considering that in the future then as I indicated the 650 would be a good choice.

 

[delluser1]

Hello Guys,

I purchased Sapphire HD6850 some days back.
It is working fine.
Problem is while playing games monitor screen flickers / fluctuates (like vibration waves).
But when I close the game, all works fine. Also while watching movies, there is no flicker on the monitor.

The system I am using is Dell Precision Workstation T3400.

I think this problem is due to my PSU which is 375W only.
When I play games, card might be asking for more power than idle state, that's why screen flickers
But not sure about it, so want opinion on what could be the reason.

NOTE: I am not facing problems of shutdown or freezing.

Any Idea?

Always love the answers to these questions.
I've used a modified, 6 year old Dell 375w to power a pair of 8800GTS 512's. The power draw of a single 8800 is the same as a 6850.
Had a GTS 450 OC with a 9800 GT ( for Physics ) running on one just a couple of weeks ago.
While your psu may be faulty, it's not very likely that your issue is due to " having insufficient power for a 6850 because the psu is only 375w "

 

[rog02]

Always love the answers to these questions.
I've used a modified, 6 year old Dell 375w to power a pair of 8800GTS 512's. The power draw of a single 8800 is the same as a 6850.
Had a GTS 450 OC with a 9800 GT ( for Physics ) running on one just a couple of weeks ago.
While your psu may be faulty, it's not very likely that your issue is due to " having insufficient power for a 6850 because the psu is only 375w "

I observed that this problem occurs only when I play "The Witcher". When I play Crysis or Battlefield (BC2), they run fine. It is strange but true. I play these games with max. possible settings on 1280 x 1024 resolution.

 

[delluser1]

I observed that this problem occurs only when I play "The Witcher". When I play Crysis or Battlefield (BC2), they run fine. It is strange but true. I play these games with max. possible settings on 1280 x 1024 resolution.

No chance of the psu being your issue.

 

[monu_08]

you should have pci x6 power connector port 2 i would recommend 700 watt zebronics or gaming way cooler master smps or best corsair note you should use atleast 600 watt psu to run quietly

 

[RetiredChief]

^ Out in left field.

Agree with Delluser if two games (with simular PSU demands) run fine and not 3rd, most likely software.
That said, I'd still verify my 12 V raill while running either prime 95, of furmark. I do this on "oustanding" PSUs that should have no problem running my system.