GTX 750Ti on a X4 PCI-E port

[iSkylaker]

Hi there

I recently got a GTX 750Ti, I'm about to install it on a AM1 board for testing and benchmarking with an Athlon 5150... the GPU has no PCI-E connectors, which means all the power it will get is from the PCI-E slot. The problem is, the board has a X1 PCI-E slot and I think I heard/read that PCI-E ports can provide a limited amount of power, I presume a X4 PCI-E is even more limited, so what are the chances of burning the whole thing If I use the GPU on that PCI-E slot?

This is the board I got:
http://i.imgur.com/nFm3MRw.jpg

And yes, I'm aware I'll get a massive bandwidth bottleneck by using this GPU on a PCI-E X1 slot and that AM1 Kabini is and has never been a platform for games. Thanks.

 

[ShintaiDK]

Just check the manual if there is any exception. (It should be 75W since its the only port and people have used dGPUs before)

PCIe x16 is 75W, x4 and x8 25W and x1 10W per default.

 

[VirtualLarry]

Standard says PCI-E x1 slot can provide 25W, x16 slot provides 75W, don't know about x4.

 

[iSkylaker]

Just check the manual if there is any exception. (It should be 75W since its the only port and people have used dGPUs before)

PCIe x16 is 75W, x4 and x8 25W and x1 10W per default.

well, the manual illustrates that It should not be connected on other PCI-E slots but x16, although I have the feeling this is just a generic manual for all the EVGA cards nowhere mentions it is for this GPU in specific, in fact the manual doesn't even have specs or anything about this card.

I previously tested a 58W-TDP EVGA GT 220 on this slot, Windows boot'ed fine, although with no drivers installed and at a very low resolution, I presume the hardware wasn't being taxed or significantly used so I believe GTX 750Ti would probably boot to Windows too, what I'm concerned is what would happen when it get to draw more than the slot's supply limits, would it cause any sort of damages to the GPU or would Windows just simply crash?

 

[ShintaiDK]

By manual I mean the mobo manual.

Its no secret the card needs a 75W port.

I dont think you damage anything. You just get errors instead.

 

[iSkylaker]

By manual I mean the mobo manual.

Its no secret the card needs a 75W port.

I dont think you damage anything. You just get errors instead.

ah, gotcha.

In that case I'm going to try it then, I'll report back if anything happen.

Thanks.

 

[PG]

I did this a while back with an extra ITX system I had. MSI AM1 ITX, 5150, and EVGA GTX 750 SC 2GB. I was too ignorant to even think of this issue, but I don't remember having any problems. Of course I was just playing around and only ran 3D Mark a few times out of curiosity. I think it got around 3300 in Firestrike if I remember correctly.

 

[RU482]

you need something like this:
http://www.frozencpu.com/products/20752/cab-1907/PCI-Express_PCI-E_x1_to_x16_Adapter_Cable_Riser_w_Molex_and_Capacitor_-_7.html

 

[nenforcer]

you need something like this:
http://www.frozencpu.com/products/20752/cab-1907/PCI-Express_PCI-E_x1_to_x16_Adapter_Cable_Riser_w_Molex_and_Capacitor_-_7.html

People used those for mining rigs - but it won't magically increase the amount of Wattage your graphics card is able to get just because you now have a full x16 plugged into a x1 slot.

It's absolutely worth a try - just make sure your monitor is plugged into the dGPU. The worst that could happen is you get a message on the screen that says

PLEASE MAKE SURE THAT THE PCI EXPRESS CABLES ARE PLUGGED IN

if there isn't enough power being recieved by the card.

 

[iSkylaker]

Hi again, I installed the GPU yesterday and is been working just fine on the X4 PCI-E slot since then, no issues whatsoever, I've been testing a few different games some which have got 80%-97% of GPU usage and still no problem.

I'm starting to believe based on this pinout diagram that PCI-E slots, regardless if is x1, x4, x8 or x16 still is supplying the 75W. All the Voltage pins are under the PCI-E x1 mark the rest are ground pins and pins for data, althought if that's the case, whats the point of a PCI-E x1 to PCI-E x16 power riser?

 

[nenforcer]

Hi again, I installed the GPU yesterday and is been working just fine on the X4 PCI-E slot since then, no issues whatsoever, I've been testing a few different games some which have got 80%-97% of GPU usage and still no problem.

I'm starting to believe based on this pinout diagram that PCI-E slots, regardless if is x1, x4, x8 or x16 still is supplying the 75W. All the Voltage pins are under the PCI-E x1 mark the rest are ground pins and pins for data, althought if that's the case, whats the point of a PCI-E x1 to PCI-E x16 power riser?

The only reason I can think of is to save space - which is what people did with mining rigs. You can have a dual slot graphics card plugged into each and every PCI-E slot - unless you use those riser cards. You can then have the graphics cards suspended above for better air cooling.

 

[LTC8K6]

Are you using something like GPU-Z?

You should watch the GPU clock speeds and tdp numbers.

The GPU could be throttling.

 

[Stuka87]

Yeah usage percentage does not tell the whole story. MSI Afterburner will graph out the GPU usage and the clock speeds over time.

 

[PliotronX]

Hi again, I installed the GPU yesterday and is been working just fine on the X4 PCI-E slot since then, no issues whatsoever, I've been testing a few different games some which have got 80%-97% of GPU usage and still no problem.

I'm starting to believe based on this pinout diagram that PCI-E slots, regardless if is x1, x4, x8 or x16 still is supplying the 75W. All the Voltage pins are under the PCI-E x1 mark the rest are ground pins and pins for data, althought if that's the case, whats the point of a PCI-E x1 to PCI-E x16 power riser?

It was my understanding as well that the power supply pins are the first handful towards the video output and the further out pins are just repeating data lanes. Per Tom's Hardware, x4 barely affects performance with x1 being the obvious bottleneck but still useable.

 

[Madpacket]

FWIW I've hooked up a Geforce 750 TI to a 1X PCI port on an older AM2 ITX board. I had to short a few pins and melt the end of the PCI connector but it worked just fine.

I also hooked the same card up to a Socket AM1 AsRock but this had a 16X connector.

I agree with your assessment, I think 75W is still supplied (at least on ITX boards) with only one PCIe slot. Perhaps if you run an ATX board board with multiple PCIe the 1X or 4X slots will have different power characteristics.

 

[iSkylaker]

Are you using something like GPU-Z?

You should watch the GPU clock speeds and tdp numbers.

The GPU could be throttling.

This is BF4 at ultra without MSAA, is playing in one of the least GPU and CPU instesive maps, I'm going to take more screenshots and record some clips of The Witcher 3 later tonight which is more GPU intensive from what I've seen and is the one who I've noticed to peak to the 80%s of GPU usage.

 

[LTC8K6]

Well, you can see that Maxwell efficiency...

 

[SPBHM]

that's a seriously slow CPU for gaming, it shouldn't be surprising, and for BF4 maybe 260x+mantle would give you a better result...

x4 2.0 is also a bottleneck, but not that bad

anyway, some of the settings from the ultra profile are also more CPU dependent, try low or medium profile or adjust those settings

 

[nenforcer]

that's a seriously slow CPU for gaming, it shouldn't be surprising, and for BF4 maybe 260x+mantle would give you a better result...

x4 2.0 is also a bottleneck, but not that bad

anyway, some of the settings from the ultra profile are also more CPU dependent, try low or medium profile or adjust those settings

My new Windows 10 machine is build on an ASSRock 990FX Extreme 9 AM3+ motherboard which is apparently unable to run a second graphics card at anything higher than PCI-E 2.0 x4. This is despite the advertising and manual all claiming to support SLI and Crossfire at dual x16 speeds. Apparently this motherboard is the only 990 FX one which can't do this. *sigh*

SLI requires at least x8 but Crossfire doesn't have this limitation. I've actually been playing Battlefield 4 using Mantle and haven't noticed any problem with the second card running at PCI-E 2.0 x4 speeds.

 

[iSkylaker]

that's a seriously slow CPU for gaming, it shouldn't be surprising, and for BF4 maybe 260x+mantle would give you a better result...

x4 2.0 is also a bottleneck, but not that bad

anyway, some of the settings from the ultra profile are also more CPU dependent, try low or medium profile or adjust those settings

Indeed, this CPU is a no no for anything gaming related really. Maybe for those LoL type of games with a dGPU. Admittedly, from the games I tested I got slightly better performance than expected even considering the possible PCI-E x4 bottleneck, still for the most part it is a bad CPU, some game just doesn't matter the settings there is always bad performance and very unstable gameplay at some point.

The only one that really surprised me was The Witcher 3's performance, with all the heat it got few weeks ago about being a bad PC port, I wasn't even expecting to run it in the first place.

Here are some vids:
The Witcher 3
BF4 with PS4 settings 1080p
BF4 with PS4 settings 900p
BF4 with PS4 settings 1080p w/ motion blur
BF4 with PS4 settings 900p w/ motion blur

 

[omek]

I dunno, you've got to give it a hand for remaining above 30fps in Battlefield, the frame rate looks quite stable. You could probably turn a few graphical options up without losing any performance with the card running at such a low usage, maybe cap it at 30fps. Perfect couch computer.
The problem with the Witcher is that you may be running over your VRAM limit.

I believe the GPU will just downclock if it doesn't receive enough to boost or kick the voltage up. IIRC this has been the case since 2d clocks and variable clocks were implemented.

 

[therealnickdanger]

Very cool - thanks for jumping in and trying it! I love this kind of stuff. I know we're supposed to try to balance things and optimize for X and Y, but sometimes you just need to sculpt a vase with a jackhammer.

 

[iSkylaker]

I dunno, you've got to give it a hand for remaining above 30fps in Battlefield, the frame rate looks quite stable. You could probably turn a few graphical options up without losing any performance with the card running at such a low usage, maybe cap it at 30fps. Perfect couch computer.
The problem with the Witcher is that you may be running over your VRAM limit.

I believe the GPU will just downclock if it doesn't receive enough to boost or kick the voltage up. IIRC this has been the case since 2d clocks and variable clocks were implemented.

Yeah, but in BF4 its like the best case scenario, is one of the least demanding map and 32 players, on other CPU demanding maps the spikes are noticeable and drops can go as low as 15-18fps regardless resolution or settings. I still have more recorded footage of those maps, and more test with different settings. As for the The Witcher 3, the stutter is more about CPU because as you can see all the cores are almost always at 100%, also I'm using 8GB of RAM, the RAM usage is less than 5GB on that game.

Very cool - thanks for jumping in and trying it! I love this kind of stuff. I know we're supposed to try to balance things and optimize for X and Y, but sometimes you just need to sculpt a vase with a jackhammer.

No problem, I still have some more games (GTA V, Borderlands PS and BF3) that I've tested and footage recorded, I'll post more later. I wish I had a better upload speed.

 

[PingSpike]

People used those for mining rigs - but it won't magically increase the amount of Wattage your graphics card is able to get just because you now have a full x16 plugged into a x1 slot.

It's absolutely worth a try - just make sure your monitor is plugged into the dGPU. The worst that could happen is you get a message on the screen that says

PLEASE MAKE SURE THAT THE PCI EXPRESS CABLES ARE PLUGGED IN

if there isn't enough power being recieved by the card.

I thought half the point of that particular riser was that it exposes a molex connector attached to the slot. No idea if that *actually* helps with the power but that certainly seems like the idea.

 

[DustinBrowder]

Hi again, I installed the GPU yesterday and is been working just fine on the X4 PCI-E slot since then, no issues whatsoever, I've been testing a few different games some which have got 80%-97% of GPU usage and still no problem.

I'm starting to believe based on this pinout diagram that PCI-E slots, regardless if is x1, x4, x8 or x16 still is supplying the 75W. All the Voltage pins are under the PCI-E x1 mark the rest are ground pins and pins for data, althought if that's the case, whats the point of a PCI-E x1 to PCI-E x16 power riser?

All should provide 75W, the issue arises when you use more than 1 slot. For example if you were to use E-16x, 4x and 1x, you wouldn't be able to do it.

As long as you are using just one pci slot it should be fine!