Powering GPU with connector on watt limited PCIe?

Toggle sidebar Toggle sidebar
X

Xenone

Reputable
May 19, 2016
114
0
4,690
My PCIe is locked to 35W, could I get a GPU for exmaple GTX 600 series or GTX 900 series and plug in the 6 pin power connector and use that to power them? Or will the GPU try to draw the 75W thru the PCIe and fry the motherboard?
 
Solution
clutchc
That's the typical Dell disclaimer to keep you from using a gfx card that draws more power than the tiny PSU can handle.
I have a similar SFF PC, a Dell Optiplex 790. It has a 275W Dell PSU with a +12volt rail rated at 17A. I have had no issues running my GTX 750 Ti in it for over a year now. Maxing out both GPU and CPU.
http://imgur.com/a/1Wi3n

Your 235W PSU has the same +12V rail specs as my PSU. 17A capacity on the +12V rail. If you find a low-profile GTX 750 Ti that fits your case, you should be OK. But of course, any time you go beyond the manufacturer's specs, you do so at your own risk.

But... what CPU is in your PC?
Sort by date Sort by votes
Sounds like you have a pre-built system. Dell? The 35W limitation listed on the motherboard and in the manual is more of a disclaimer for the tiny power supply accompanying the PC than the slot/board itself. List the make/model of your PC, please.
 
Upvote 0 Downvote

It's a Dell Optiplex 960 Small Form Factor, I have contacted Dell and they told me that some people tried to use GPU that draw more than the 35W and it worked like a charm, and some had no luck, when I asked them what would happend if I power the GPU thru the 6 pin connector and they said they never seen anyone do it and they never tried it so they can't answer that, thats why I though maybe someone knows if this can be done.
 
Upvote 0 Downvote

I wanted to put in a 750Ti since it's the best GPU that I could find in low profile but as I was measuring the space if it would fit or not, I noticed that it said 35W under the PCIe slot, it looks like this:
297d230456572b5ad4954c5793ece7d6.jpg


 
Upvote 0 Downvote

I did find this review on a a 750Ti, excatly the same that I was looking at and the guy said this:
"After researching all the available Nvidia GPUs out there, this was the most powerful available in a low-profile short card format that would fit in a Dell SFF. Depending on the space available in your computer, this video card can be made to fit but you may have to modify it and the computer itself.

I have it currently installed Inside a Dell Optiplex 960 but needed to make two small notches in the plastic fan cover and heat sink to clear a capacitor and the Ethernet connector on the motherboard. This required using a Dremel and some trial and error to avoid cutting away more than necessary. In the end it was a perfect fit with less than 1 sq inch of area removed from just one of the dozen horizontal heat sink fins.

The next obstacle was the hard drive caddy which interfered with the video card's fans and cover. Fortunately the SFF I am using is already outfitted with a 2.5" SSD which is light weight and doesn't need the full caddy space for a 3.5" drive. Using the Dremel again, a narrow portion of the caddy was removed along the edge that needed clearance for the video card fans. The old 2.5" to 3.5" adapter was removed and the 2.5" SSD was mounted directly to the caddy with double sided foam tape. Given how light the SSD is, I am not worried about the foam tape losing grip and having the SSD fall on the motherboard.

One concern I often read about and also see mentioned is the required power supply wattage. Reading up on the GTX750Ti design and other GPUs, a majority of power is obtained from the +12V bus. Test reports show this GPU requires 64 watts on average but let's round that up to 72 watts. This only requires 72/12 = 6Amps from the power supply where the Optiplex 960 SFF spec claims 17Amps maximum on the +12V bus. Given the SSD is not power hungry with +12V, there is likely ample margin on powering the GTX750Ti even though the SFF power supply is stated as 235W max.

For those of you looking for the most powerful Nvidia GPU in this form factor, I would recommend this MSI N750TI-2GD5TLP graphics card."
c7417b694c8f8a13e029e9425097f914.png

435da6a94a6dad968f7978b6b8964f32.png

The guy claims he did put in a 750Ti in his Dell Optiplex 960 SFF and even provided pictures, he never mentioned anything about the 35W sign, he also never said if he uses the GPU at full load, because he could be simply using it to watch videos and not actually push the GPU to over 35W.

 
Upvote 0 Downvote

That's excatly what I'm thinking, because Dell themselfs said that people did put GPU's inside the 960 SFF that used more than 35W and for some worked like a charm, but for some didn't, but I don't know what kind of GPU's they used, all we could know that for the people's who didn't work, could've used a beefy GPU that used 150W and they pushed it to full load.

I googled what PSU does 960 Desktop have, and it says it's a 255W, and the 960 SFF has 235W, after Googling 960 Desktop motherboard
c3c13e2df1eebaabd18318a3864ae732.jpg

You can just about to see it that it also has the 35W sign, even tho it has bigger PSU, which has exploded my mind because I don't know what to think now.

 
Upvote 0 Downvote

It could be, I just don't want to put a 750Ti in, run a benchmark and push it to full load just to find out that it fried by motherboard.

 
Upvote 0 Downvote
the motherboard is unlikely to have the inablity to supply the power, for instance the ATX connector is rated at 375W. it is unlikely that the engineers would bother restricting this number on the board its self, as that would be a waste of materials. thus the more I think of it, the more it makes sense that it is the PSU limitation.
 
Upvote 0 Downvote
That's the typical Dell disclaimer to keep you from using a gfx card that draws more power than the tiny PSU can handle.
I have a similar SFF PC, a Dell Optiplex 790. It has a 275W Dell PSU with a +12volt rail rated at 17A. I have had no issues running my GTX 750 Ti in it for over a year now. Maxing out both GPU and CPU.
http://imgur.com/a/1Wi3n

Your 235W PSU has the same +12V rail specs as my PSU. 17A capacity on the +12V rail. If you find a low-profile GTX 750 Ti that fits your case, you should be OK. But of course, any time you go beyond the manufacturer's specs, you do so at your own risk.

But... what CPU is in your PC?
 
Upvote 0 Downvote
Solution

That's very true, unless this is possible to be done with BIOS, but I doubt it, I will propably get a 300 or 350W PSU and give it a shot.


I got a Xeon X3323 6M, the 960 SFF has LGA771 socket so there's not a lot of choices. I will need to upgrade the PSU to 300 or 350W, the 235 it's not going to be able to handle, I have ordered a PSU adapter for the 960 SFF about a week ago and I will see if it fits or not, if not then I will need to get XE 280W PSU which 100% works with 960 SFF but they're very pricey.

 
Upvote 0 Downvote
Just recived my Optiplex 960 SFF to ATX Motherboard power connector adapter, now, when it comes to PSU's, can I just put in any watt PSU? Like 500W, or is the Optiplex 960 SFF rated do a certain wattage?
 
Upvote 0 Downvote
Just ordered EVGA 430W ATX Power Supply, I have 20% discount on EVGA parts on a novatech and I couden't find a 400W EVGA PSU on there but 430W should be fine and I also ordered the MSI GTX 750Ti Low Profile GPU, everything should come in next 3-5 working days. I will take pictures and document the whole process and make a final conclusion since from the looks of it, I will be the first person to document if a 750Ti can go into 690 SFF because the only information I could find, is a guy installing one and how he modified it to fit in the case but never said what PSU he has ect.
 
Upvote 0 Downvote
So I just got the power supply, I plugged it in and it boots but it's dosen't go past post. I get this error message:
WI2vHai.jpg

Ignore the Drive 0 & Drive 1 not found, I have removed the CD-Drive as it was taking up 1/4 of the case and I never use it and I get this window everytime I boot up but I press F1 and it starts up properly, so I have removed the EVGA PSU and plugged in the stock one and I still got the window up about the Drive 0 & Drive 1 but I pressed F1 and it went past post and booted up. It says AHCI BIOS not found, I don't get this with stock PSU, as far I'm aware, but I'm not sure what PSU has to do with BIOS.
 
Upvote 0 Downvote
Ignore what I said above, stupid me forgot to plug in the SATA cable to the hardrive.
EDIT: After I plugged in the SATA, it works perfectly fine, I also just recived the PCIe ribbon cable extension for the GTX 750Ti, I got everything except the GPU itself, hopefully it will come in tomorrow or even today.
 
Upvote 0 Downvote
I got the GPU today, a week later because TNT lost it. But I got it.
Now, I have plugged everything, started it up, and the PC would cut the power as soon it reached POST. After playing around for an hour, I figured out that the PC couden't start because it couden't recognize the GPU, which is strange, so I put in my old GPU back in, downloaded the latest drivers & MSI Afterburner (even tho the 750Ti came with the driver & MSI afterburner dics but it was useless since it wouden't go past post), it has fixed the issue, but then, as soon I reached the "Starting Windows" screen, the PC would freeze with a stastic noise, after more digging around, I figured out that in BIOS, you have to disable that if a the PC can't find a GPU in PCIe, it would start with intergrated GPU, after looking in logs, it turned out that the BIOS would start the PC with the 750Ti, but then tried to overide it with intergrated GPU and it would crash the system (strange as I never used intergrated GPU, always a GPU inside the PCIe and never had this issue) so I fixed it by turning off the option that the PC would start with intergrated graphics if there's no GPU in PCIe. After waiting about 10 minutes for the drivers to install so I don't have 600x800 resolution, I had to restart the PC, everything was fine, after the restart the resolution was fine, I started off by opening a YouTube video to put small stress on the GPU, as soon it would load the video, the PC would cut off power (at first I though it was a faulty brand new PSU, but after looking in the logs, it turned out that the PC would cut off power because it had "Power saving" enabled in the BIOS and with the stock PSU, it would lower the wattage but since I no longer run the stock PSU, it just dosen't know what to do so it cuts off the power complety, I fixed it by turning off "Power saving". So far everything has been working fine after that chaos. Now I understand why people don't put GPU bigger than GT 730 inside Optiplex 960 or atleast small form factors, because they cause a lot of issues. I will run a benchmark on the GPU in couple of hours after it gets a small use as I just got it working and don't want to instanly put max load on it as soon it came out of the box. I have put the fans on max speed (you will know why after looking on the pictures) I have taken few picture of how the setup looks so far. It's very haggard and doggy, but I'm waiting for my friend to comeback from his holiday so he can borrow me his dremel so I can cut an inch of plastic from the GPU to make it fit over 2 capacitors. For now it works fine.
11ea949a7bc840429c72ad76e347a0c3.png

Yes indeed, that's the GPU upside down on top of the ram, with the ribbon cable supported by a cardboard square so the GPU dosen't collapse on top of the ram. After taking the picture, I put one fan behind the PC so it can get cold air and one inside the case to suck the warm air out so it dosen't warm up the ram.
34ebb40b9fab414bb6501616000e836a.png

That is the back, all the cables coming out thru a hole where the stock PSu used to be, the EVGA 430W PSu dosen't fit inside in anyway so it has to be outside, the GPU has a big hole to suck in the air (where I have put a fan by), by doing simple task, it's an normal temptures so no issues with this yet.
The max watt I have reached so far is 19W on the GPU, I haven't passed the questionable 35W, I will when the I will run he benchmark and that's when the truth will come out.
 
Upvote 0 Downvote
After running a stress test, I have managed to push the GPU to 100% load and 95% power consumption, and everything worked fine, I had the stress test on for 15 minutes and everything was fine, opened few games like GTA V to test it in real scenario, got the GPU to 50% power consumption and everything was fine, I was going to measure the tempture of the motherboard to see if I'm putting a stress on it incase it has some sort of watt limited and I was overloading it but since the motherboard is so small, the south bridge always keeps it hot so there was no point. It turns out that infact the "35W" next to the PCIe was just a warning for the stock PSU. Thanks both of you for help, I guess this was finally cracked after 7 years.
 
Upvote 0 Downvote
Excatly, there's not a lot of infomation on the Optiplex 960 SFF, from the look of it, Optiplex 755 is a more popular & common choice because it costs quarter of what the 960 SFF costs. The most valuable information I could find was a guy leaving a review on the 750Ti on a Amazon page on how he managed to fit it in the 960 SFF, and since the 960 SFF has been around since 2009, you would expect that there's a decent amount of infomation about them out there. I love those 960 SFF because it suits my needs and it's my most reliable PC I have ever worked on, which is why I sometimes I question myself, why they're not as popular as they should be. I have many and many upcoming plans for the 960 SFF, like water cooling, possibly extra hardrive, which I'm sure I will write about it, so people in the future can find infomation about it, just like how I wrote how to get the 750Ti working with it.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom