HP Z840 4 GPUs and PSU

[Pierre-S]

Hi,

I would like to buy a workstation hp z840 and include 4 gpus gtx 1080ti . The PSU is 1125 W but as I am living in UK the input voltage is 230V. So, if I am not wrong, the PSU will be about 1450W. So that should be ok. I was thinking to use 3 PCIE 3.0 x 16 and 1 PCIE 3.0 x8 (it seems the x8 works well on GTX 1080ti too).

But, I was wondering if there will be enough pins. In fact, the GTX 1080ti use 2x 8 pins. Is it possible to got 8 x 8 pins for my gpus ?

If yes what should I do ?

Thanks !

[DGroves]

no you can not run 4 1080 TI video cards in a z820/z840 even with the upgraded power supply

the power supply in the z820/840 systems is a multi rail supply NOT A SINGLE RAIL DESIGN, as such trying to run four video cards will overload the 12volt GPU rail causing the cards to either not display when under a 3d load or random video shutdowns

since the 1080 TI series draws 250 watts (or more) four cards would be 1000 watts load on the GPU Rail which far exceeds what the rail can safely output

https://www.google.com/search?rlz=1C1CHBF_enUS850US850&biw=1278&bih=787&ei=ZmCHXZTMII2c_Qb1v6qIBQ&q=...

[Pierre-S]

Hi,

I thank you for your answer.

Do you know how many gpus the hp z840 can take ?

[DGroves]

i'm not going to answer this question as it's almost impossible to do so

the limiting restrictions are 

1. number of free slots in your system

2. the wattage of the GPU cards you wish to install (should not exceed the HP recommended total)

there is very little need for multiple video cards in a system for most users and the few users who do need

(or can make use of) multiple video cards are using specific software applications

go look at what video/coprocessor options HP offers in the z840, and note the total wattage of this and use it as your max wattage