75W GPU on the PCIe with 25W limitation ?

rezamm

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Jun 6, 2017
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hi guys.
i have a HP compaq 6005 pro SFF pc :
1-240W PSU
2-Phenom II x4 B97 at the 95W TDP.
3-180GB SSD
4-PCI-e x16 2.0 at the 25W max.(written in manuals.)

so i wanna to buy a Nvidia 750 ti with the 75W TDP and the PCI-e 3.0 platform.
how can i do that? by bios changes? or i cant use that card ?
 
Solution
Ohh its one of those 12 volt only units. Assuming the -12 volt rails are not heavily loaded you should get pretty close to the full 240 on the 12 volt rail(- whatever else is required for 5/3.3 that must be generated on the board).

Your quote from noormanman seems to indicate someone has in fact managed to add a video card to such a system. This would mean it should at least be possible. The loss a x8 if required should be under 10%.

The problem and the reason no one will say "sure, go for it" is because no one wants to be the person who had you buy a new video card that does not work or kills your power supply(since it is custom it is not as easy to replace).

Jesse_20

Distinguished
An upgrade to PCI-E 3.0 requires a newer motherboard (and most likely cpu, and ram) that supports it. It is hardware on your board and can't be upgraded. As suggested, I'd buy a new system and add your current ssd to it.
 

While you can not get PCI-e 3.0 speed out of older slots, you CAN run PCI-e 3.0 cards on older boards(placed a 100 into a PCI-e 1.1 slot just to test it) as long as they provide the required power(and have bios support. This is a non issue on many older systems without uEFI).

This is a power issue and you may damage something trying to run ANY card(regardless of the PCI-e version) that requires more than 25 watts(unless it has a 6 or 8 pin power cable to get the extra power it needs). The system is simply not designed to be upgraded in such a way and may also have bios limitations that prevent use of a new video card.

It is recommended to build or buy a newer system with support for a video card or you may be able to use a low powered card.
 

MatthewGB

Respectable
Jun 15, 2016
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If you buy a card with excessive PCIE power slots, it should work. One example is the Gigabyte G1 GTX 980. The GPU uses a maximum of 200W, but the power connectors allow for up to 300W. This means that theoretically, if the PCI slot could provide little power it could still run and have 100W to spare. You'd have to look around for some aftermarket models at your price point. Remember that each 6pin PCIE allows for 75W and each 8pin 150W. As long as the total power that can go through the PCIE power is bigger then your card's TDP it SHOULD run. But I don't guarantee it. Your PSU is probably too weak for any new card, and because it's an SFF case it's probably too small and you'd probably have to use an x16 riser which is going to be outside your case.
 

rezamm

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Jun 6, 2017
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=========> similar problem

anyone can explain it ? :



*********noormanman said:
Thank you for all anwsers above. I just upgraded my HP 6005 Pro SFF with an Geforce 750 Ti and it works perfectly :)
(model GV-N75TOC-2GL)
Note that I did have to change a bios setting, the PCI-e x16 slot was in x8+displayport mode, the PC did not boot past the initial bios message, nor could I acces the bios setup screen. In x16 mode everything was OK.

The HP documentation does say that the PCI-e x16 slot is limited to 25W. However, the same motherboard (type: 531966-001) and bios is used in the non-SFF chassis, and there the slot is limited to 75W (as it should). So I have to agree to americanbrian that this is only an PCI spec half height card issue, not a limitation of the SFF PC. :)

The power supply is 240W. The system uses under full processor load WITHOUT the nvidia card (prime number stress test) 136W.
This means that I have about 100W spare for my graphics card. I assume the card is max. 75W as this is the PCIe maximum for graphic cards without an extra power connection.

Further. on this power supply is a sticker which says:
12V generic rail: 14A max.
12V cpu rail: 12A max.
Total load of all rails may not exceed 240W.

This means that power supply has a seperate rail for the CPU, so most of the 12V generic rail is available for my new graphics card. as this is max. 75W (75W / 12V = 6.25A, not even close to 14A) this power supply should handle this new graphics card easily.

Playing a game (Metro 2033) the pc usage is about 150W. Despite that the graphics card does say it needs a 400W power supply, my 240W is more than enough.

Please note that this does not say that any power supply does work, the 12V rail must have enough power to power both the CPU and the graphics card. Cheap power supplies may have enough power on the 5V/3.3V rail, but lack the power on the 12V rail.

I hope my 2c can help anybody out there!************

 

rezamm

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Jun 6, 2017
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Pci e 3.0 can run in Pci e 2.0.
 

Jesse_20

Distinguished
I'm fully aware it can run in 2.0 mode. The OP made it sound as if he wanted to run it at 3.0 speeds however, hence my response.
While you can run the 3.0 in a 2.0 slot, you still don't get the bandwidth to utilize the card to it's fullest.
So, if the OP wanted to run it in a 3.0 configuration, he needs to upgrade his board.
Sorry for all the confusion.
 
It is not like the 750ti will noticeably faster with 3.0 vs 2.0 either way.

A GTX 1080 on average looses about 1-2% from pci-e 3.0 to 2.0 x16 and about 6ish down to pci-e 1.1 x16. Some games will feel it more, but a 1080 is much faster than the 750ti.

It is a gamble either way swapping cards. You HP board could be just fine or be very mad even with the GT1030.

Out of curiosity, How much power from that power supply is on the 12 volt rail? A 240 watt is pretty small and even my rather old 300 watt only has 264 watts on the 12 volt rails.

SFF systems are generally efficient and get away with less, but it would not be good to overload the poor power supply.
 

rezamm

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Jun 6, 2017
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510


HP_Compaq_Elite_8100_SFF_PowerSupply_2.jpg


1-so what gpu you offer me to buy ?
2-and the GT1030(pcie3.0) is work in the Pcie2.0 at the 90% of 3.0 slot ?
3-what can i do whit extra 5 watts of 1030? (gt1030=30W , my slot=25W)
 
Ohh its one of those 12 volt only units. Assuming the -12 volt rails are not heavily loaded you should get pretty close to the full 240 on the 12 volt rail(- whatever else is required for 5/3.3 that must be generated on the board).

Your quote from noormanman seems to indicate someone has in fact managed to add a video card to such a system. This would mean it should at least be possible. The loss a x8 if required should be under 10%.

The problem and the reason no one will say "sure, go for it" is because no one wants to be the person who had you buy a new video card that does not work or kills your power supply(since it is custom it is not as easy to replace).
 
Solution

2690173248

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Jul 7, 2016
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Hmm I am in a similar scenario with OptiPlex 755 DT and it says 25W max:
https://scontent-yyz1-1.xx.fbcdn.net/v/t35.0-12/21868430_1995307130738550_1526396297_o.jpg?oh=d2bcd61a04b1a7260c5e3282f991fdd1&oe=5A0D32F8
Even with this I am able to run a Zotac GTX 1050 Ti mini with PCIe riser and the plastic shroud of the 1050ti removed.
I hope this lasts for some time, but I am pairing it with X3363 OC to 3.2Ghz, 8GB DDR2 RAM OC to 900mhz, and 5400rpm laptop hdd + ssd to keep the TDP down. The only other add in card is Ethernet, as the Xeon BIOS mod bricked the onboard Ethernet. All that on a stock 295W PSU.
GPU-Z also reports that this card is running at PCIe @ x16 1.1 perfectly (though I learnt the hard way that the cheaper cards like to run x8 in a x16 slot, and O755 doesn't support x8 so it ran at x1 instead)
Still runs just about anything and is quite capable
You could say the pairing is pretty unbalanced, but for certain game titles such as Witcher III, 1050 Ti holds X3363 back with less than 50% CPU and constant 99% GPU (at least in my monitor's 1680x1050 resolution)