OTOY Forums

I recently made the move to a PC and got an X99 board to accommodate many GPUs. I have 3 980 ti's in there now and its great.

I also have an amfeltec PCIE expansion rig, how many cards can I extend that last PCIE slot too before the motherboard runs out of lanes? I have way too much PSU on the inside so that should not be an issue. 1600W on the inside plus a 1200w for external. There is a lot of talk here about how smooth power matters with GPU rigs, I chose overkill.

Can I actually get 7 cards running with 3 inside and 4 in the amfeltec? I feel like I would fry something and am afraid to test that out. I am not too worried about the 1x slowdown as I was using it on my old mac pro and the load time never became a giant issue.

Also, would I still be able to overclock my CPU with that many cards going into it? Would it restrict the SATA space?

lots of questions, lots of testing to do.

Thanks.

As to the X99 MB, I have no experience, but I'm running 2 680's internal and 4 660ti's external with no apparent issues on Win7pro with an older X79, 3930k setup.
More of the problems that I have had seems to be with Windows 10 1703 (latest edition) and/or my MB.
I will say my issues could be a variety of things and not totally related to Win10 at 1703 level.
It may be that at the 1703 level it doesn't like my older hardware or something else, but I've had a lot of stability issues running an Amfeltec array with Win10 1703. (Win10 1607 was no problem.)
(It may also be related to which Amfeltec device you have... although I would tend to think they perform the same type of interface with the pc..)
There is a fairly good thread regards multi gpu setups here..viewtopic.php?f=40&t=43597&p=308499#p308499.

With the x79 MB I have, I understand it has 2 x16 slots and a third x8, so it should have theoretically worked, but I could not get the third PCIE slot to work stable with two 680's in the primary and secondary x16 slots. Reason unsure, but I believe it was to do with my MB not having any facility to change the main 2 GPU slots to a be x8 or some other variable (if it sensed that they were occupied by GPU's). (ie x16 x16 x8 = 40) and I have other peripherals using resources that I couldn't do without, so it kept throwing a code 12 and no resources errors from time to time... not every time, but enough to make it not workable.
Whereas afaik my Amfletec is a pcie x4 splitter each downstream port is x1 (4 of) and is not an issue. As at worst afaik I believe it sees this as x16 x16 x4.
So.... to me, using a splitter/expander "should" give you more headroom re pcie lanes, if this is the main problem....
One thing I would suggest is to actually take out one of the 980ti's and trial it as that 2 980ti's and 4 external. If that is stable then put the third back in and test. (I assume you have 4 pcie full length slots?)
The other reason I would advocate more external than internal is for heat build up in the case. Yeah, running more cards at x16 should be better, but I really have not seen any problems with running the external cards at x1 and three 980ti's in a case will be pretty hot unless you water cool them... and if you do want to overclock.. maybe not the best idea. I just know that space restrictions with the two cards I have, one is quite close to the PSU and is hotter by at least 6-8 deg that the other one that is clear of restrictions and the externals can be up to 10 deg cooler again.

amfeltec splitter makes the computer see more lanes?
can you please elaborate. Because i was told from the local computer store that even with the splitter my i7 cpu will only be able to handle 5 gpu max.
If this is not the case it would be great because it would save me buying another whole desktop. It would be nice to run 6 to 7 gpu. i have 3 780s now and a single slot gainward 750 for viewport.

check this bad boy out.

http://galaxstore.net/GALAX-GeForce-GTX ... p_130.html

single slot gtx 1070. wonder when itll be back in stock.