GPU underpowered or wrong connecter?

[Deviant Savant]

I recently bought an AMD Radeon HD 7900 Series GPU and it is rated as needing 375W under full load. So I thought my low end spec PC would be okay with this and my PSU is 650W but only uses 118W under normal load. I know this means little because my PSU is not going to be as efficient at an 80+ Gold or Platinum and now there are Titanium rated PSUs for consumers PCs...tempting...

My question is: what benchmark software should I use. I would prefer to have one that allows me to get a reading on the power drain, so I can gradually increase power use of the GPU, I don't care what test benchmark for this purpose since I am only wanting to test pwoer use and see if PC cuts out.

So far PC cuts out when I try to refresh Windows Experience Index Rating under W7 x64 and the same happens when a PC game attempt to do its own tests for optimal settings. PC just shuts off and restarts. This seems not like a software bug but a PSU issue.

This bring me to the connecters I am using and if this could cause the same problem. My PSU only had one 6 pin connecter for a GPU and I needed two because my GPU is a 7990. I had to buy an adapter 6 pin PCI-e to 4 pin power adapter. This has two molex females and one has 3 pins and the other two (if memory is correct). Not sure why the molex are like this but I connected it and it seems to provide enough power. I couldn't find a local store that had a straight 6-8 pin adapter.

My GPU came with two 6-8 pin adapters but I was lacking an additional 6 pin connecter from my PSU. See images for illustration.

No problems being caused by connecting power to GPU this way?

Thank you for your help, much appreciated.

 

[Sakkura]

What is the make and model of your power supply? If it's not a reliable model, the 650W rating may simply be a lie. The fact that the unit only has a single 6-pin PCIe power connector certainly suggests that it isn't really capable of delivering 650W.

 

[BlankInsanity]

Sakkura is right, you also need to take into account if the +12V rail is supplying enough amps.

If you do wish to get another PSU may I suggest the XFX 650W PSU? it's a re-branded Seasonic PSU which makes some of the best PSUs out there

 

[VincentP]

This system will be drawing about 41A on the +12V rails of the power supply.
If your power supply only comes with a single PCI-E power connector, there is a good chance it is simply not built to do this.
A good 650W supply can provide this power, but a 750W would be more appropriate with this video card.
You don't necessarily need 80 plus gold rated supply, but never buy a supply that is not at least 80 plus rated.
Some suggestions:
Corsair TX 750
Antec HCG 750
Seasonic G 750

 

[Deviant Savant]

Thanks for the advice everyone. I thought it was a PSU issue but had to ask since the AMD drivers can be buggy, especially for this card but I think most problems are fixed for it since first release. Sakkura, the PSu is not a brand name that is known so just a cheap one that came with no documentation even. I will be buying a new one in New Year and probably higher powered one. My CPU is an i7 2600 and I have seen other setups with less than this using PhysX. I got the GPU because it has multi-purpose uses and will be used for many years to come.

I've looked at Corsair RM80 and RM1000 and a few other top PSU companies with higher prices. Considering whether to get modular or not and if I do then I might go for a Coolermaster...need to look at more before deciding and whether I will be looking for mid or low priced one for what I need.

 

[Sakkura]

Cooler Master has some good PSUs but also a lot of bad ones. If you go their way, make sure you check some reviews of the unit first. Proper reviews, using a load tester and measuring voltage regulation and ripple (and, for extra credit, transients and hold-up time).

XFX Core Edition, Antec HCG and Seasonic S12II are all the same basic design and are often among the most affordable quality PSUs. But they're a bit old-school when it comes to features (not modular, no fanless mode).

 

[Deviant Savant]

Thanks Sakkura, I will be sure to take my time and find proper tests and reviews as much as are available.

Was thinking of using Lucid Virtu Driver just so I can use my iGPU from i7 2600 for general desktop tasks and dedicated 7990 for more intensive software and gaming. Not sure how I go about this. I read that it no longer needs to be connected to a display for shared performance? I am just looking to lower energy use than anything else for when the 7990 isn't needed. I would test this out now but I can't find my DVI - HDMI adapter.

In my case would I connect the iGPU directly to the GPU or just to my display?

http://www.tomshardware.co.uk/answers/id-1630760/lucid-virtu.html#10532323

Edit: not sure if my Virtu series is compatible across Intel-AMD but will look into it.

 

[BlankInsanity]

Thanks Sakkura, I will be sure to take my time and find proper tests and reviews as much as are available.

Was thinking of using Lucid Virtu Driver just so I can use my iGPU from i7 2600 for general desktop tasks and dedicated 7990 for more intensive software and gaming. Not sure how I go about this. I read that it no longer needs to be connected to a display for shared performance? I am just looking to lower energy use than anything else for when the 7990 isn't needed. I would test this out now but I can't find my DVI - HDMI adapter.

In my case would I connect the iGPU directly to the GPU or just to my display?

http://www.tomshardware.co.uk/answers/id-1630760/lucid-virtu.html#10532323

Edit: not sure if my Virtu series is compatible across Intel-AMD but will look into it.

Not sure what you mean by iGPU.. but I think your talking about the weak intell HD GPU within the core i7 2600. This integrated GPU is disabled once a dedicated GPU has been post by the system

 

[Deviant Savant]

VincentP: My PSu only had an output of 36 Amp on +12v rail 🙁 It blew itself up last night after my CPU was under heavy load while GPU was also in use. I put in another cheap one until I sort out PSU demands. I may need to daisy chain a few together in future but those solutions are not ideal.

Sorry for the late reply. I meant Integrated GPU that some processors have. I have an Intel HD GPU built in (yes it is weak but good for desktop environment) but I am going to be building a new system this (New) year and starting with a better chasis to provide me with enough space for expansion and cooling. I don't want anything out of its case for the time being if I can help it for safety of my kittens, they tend to nibble thinner cables than thick ones. I also want to get away from air cooling and into liquid cooling.

Lucid Virtu
The technology is pretty neat, it allows you to launch apps specifically with dedicated GPU while using iGPU for desktop. So any application that requires intensive reosurces will be given them and desktop environment for just running windows explorer and word, etc can use Integrated GPU. That was my thought anyway, I never bothered using this so I am not sure how glitches or bugs may affect this. I am not sure if I will be using this now though and most of the processors I have been looking at lately do not have iGPU.

http://lucidlogix.com/product-virtu1.html

Once I start building my new rig I want to get more GPUs in the near future, maybe 7 in a single case (total cost of rig would be around up to $8,000+ going with AMD GPUs or double that or more with Nvidia) and I found a few nice motherboards that support this. Only thing is PSU issues because I do intend to utilize full load on all GPUs for some GPGPU computing.

I haven't yet decided if I will go with Nvidia or AMD Radeon. I know the 7990 outperforms Nvidia with OpenCL. My main challenges are PSU demands and liquid cooling solutions for GPUs. The energy use on the GPU side depends a lot on what brand they are, I've seen some 7990s rated at 750W while the one I have is only meant to use 375W. Will be interesting to see how much it really uses once I get a decent PSU.

I've never built any liquid cooling before and the kits available for GPUs are very limited. I am going to build this instead of using a server rack setup which I was originally considering to do for GPGPU financial computing. It seems Nvidia are better at double precision compuitng than AMD GPUs. I am not sure which cards to go for at this early stage but need ASICS that are good at crunching numbers and finding dynamic patterns from data that I define or instruct it to look for. Anyway, this is my project for 2014.