Is 4790K IS bottleneck 4 way crossfire ???

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mrbig3d

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Oct 5, 2012
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system spec:
i7 4790k
mobo: gigabyte z97 g1 gaming editio
memory:16gb 1866mhz
gpus cards: 4x amd r9 290 4 way
psu: lepa 1600w

----------------------------------------------------

i have a problem run all 4 cards in full usage 100% with this cpu i run crysis 3 for example
only one card running in 100% the 3 other cards run at 30%-70% according to msi afterburner

i tested this cards on motherboard gigabyte x79 up4 with 4930k cpu - 2011 i was able to get 100% utilization in all 4 cards in crysis 3

are my suspicions are correct are 4790k can bottleneck 4 way crossfire ? because lake of PCI Express Lanes ? (only 16 max according to intel spec site)


thank you for the help in advance



 
Solution
H
heres some basic limitations...
intel i7 on socket 1150 is limited to 16 shared pci-e lanes if you have 2 cards they will both run at x8.
if you run 3 cards your pci-e is divided to 8x4x4 regardless of what pci-e your motherboard handles.
if you run 4 cards the pci-e is divided into x4x4x4x4.
your cpu is limited to 16 lanes total for all gpu's regardless of how many lanes your motherboard has.
there are boards that run pci-e splitters which allow you to run 2 gpus of 8 shared lanes but this increases latency to the point its unworkable of socket 1150 1s you get over 2 cards.

if you wanted to run 4 cards at there max potential ou will need socket 2011 but even then the drivers will cause issues as there not really written with 4 gpu's...
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looka273

looka273

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Which cards do you have in crossfire?
As for one GPU @ 100% most modern games don't handle more than two GPUs well (as in they don't use them).
Are you having any perfomance issues?
 
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H

HEXiT

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Mar 13, 2011
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4 way crossfire doesnt work mate. you want 2 gpu's max any more and your just throwing money away.
the pperfomance delta is something like this
1 card 100%
2nd card 70-95%
3rd card 30-50%
4th card 4-10%

so in real terms you would buy 4 cards and get the perfomance of maybe 20%-25% above that of 2 cards. its just not worth the money.

if your that desperate for a multi gpu then get 1 of the r9 295's. it will have all the perfomance you need for crysis 3...
oh and dont be fooled by the low fps in the first level benches. the authours broke the rope mechanics which cuts fps by over half of that they should be. pretty much any single card over a 660ti/r9 270 can max out crysis 3 1s you get off the intro level.
 
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mrbig3d

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hi there thank you all for replaying,
first i am playing at 4k not 1080p ,and i did mange like i said to scale 100% from 4 gpus of 290 with 4930k cpu at a friend of mine , in games like tomb raider , splinter cell black list , and crysis 3, batttelfield 4,

all games run at 4k , it is clear to me that for 1440p or 1080p 2 cards will be fine , but i am running 4k , which make this games and other to use the extra gpu

my mobo g1 z97 gigabyte does run (x8,x8,x8,x8) for gpus, my problem is that with with 4790k which i overclocked it 4.6 , the gpus scaling is horrible for 4 gpu (i mentioned the % in the other post)

i wanted to know if there is someone if there is a solution for it , or if i right that 4790k is causing the bottleneck?

the 4790k usage with 4 gpus in 4k is : 70-80% which is a lot

thank you again

 
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mrbig3d

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first , it wasnt a waste of money for me i bought 4 290 r9 for 1000$ used with warranty from bitcoin miner very cheap

second lepa g1600 does show in tier 1 look again please :

"""Tier one - The highest quality and most stable PSUs available on the hardware market today. Highly recommended for any situation


Antec
High Current Pro - 1200 watts
High Current Platinum series

Be Quiet Dark power pro P10 (Greater than 750 Watts)

Corsair
AX / AXi series (MK1 AX series is also an excellent choice)
AX1500i (MK3 AX platform, Titanium efficiency)

Cooler Master V series

EVGA
Supernova G2
Supernova P2

Kingwin Lazer platinum series
PC Power & cooling Silencer series (Only above 610 Watts)
LEPA G1600

Seasonic
M12 II 650 / 750 / 850w (Includes EVO series)
Platinum series (Fanless or not)
X series

Silverstone Nightjar 520w Platinum

Super Flower
Leadex Gold series
Leadex Platinum series

XFX
Black edition series
XXX series """""

 
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H

HEXiT

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Mar 13, 2011
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heres some basic limitations...
intel i7 on socket 1150 is limited to 16 shared pci-e lanes if you have 2 cards they will both run at x8.
if you run 3 cards your pci-e is divided to 8x4x4 regardless of what pci-e your motherboard handles.
if you run 4 cards the pci-e is divided into x4x4x4x4.
your cpu is limited to 16 lanes total for all gpu's regardless of how many lanes your motherboard has.
there are boards that run pci-e splitters which allow you to run 2 gpus of 8 shared lanes but this increases latency to the point its unworkable of socket 1150 1s you get over 2 cards.

if you wanted to run 4 cards at there max potential ou will need socket 2011 but even then the drivers will cause issues as there not really written with 4 gpu's in mind because amd know they dont scale very well past 3 regardless of platform.

as for gaming at 4k. the hardware isnt there yet mate. its all hype marketing. 4k wont be ready till the end of next year when the hardware needed to run the screens effectively finally arrives. currently there isnt a single gpu that can max out the latest games at 4k even with 2 you will struggle. and that tells you right there the hardware just isnt there yet.
 
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mrbig3d

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i see this a good answer thanks, but tell me please gpu-z show me all card running x8 , do it still run at x4 for all cards because of the 16 lanes?

and i dont agree with you completely about the amd drivers dont function at all with 4 gpus in cfx , i think it more game problem then driver , like i said i tested more then 4 games in 2011 all 4 gpu was scales 100% i manged to run tomb raider in 4k ultra highest settings with 4 gpus at 115-125 fps, for crysis 3 which is my favorite game was always a hard cookie to break i manged to run it in highest settings very high at 4k (expect AA=FXAA) at 80-90FPS

so i think the hardware is here i think we will start to see more and more games optimized that will use more then 2 gpus because of the 4k resolution hardware demand
 
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HEXiT

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the cards will only run at x8 if the pcie is using a splitter. basically its 2 cards sharing the same pci-e bus lanes, which means they have to do it in turns.
while both cards are technically running at x8 they are still being gimped because they can only be accesses on an alternating cycle.
generally this will reduce a crossfire 2 card setup performance by 30%+ and will affect both cards not just the second.
if you add more cards the problems get worse.

on socket 1150 it really is a waste of time. on 2011 its a little better but instead of the pci-e limiting the cards its the cards themselves and there drivers.
so if your determined to ignore us and go ahead then go socket 2011. it will do what you want but honestly the results on most games will be disappointing.
 
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HEXiT

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no mate they are optimizing for 2 cards max for 4k currently and next year we should see single cards that can handle a 4k display and give a minimum of 35 fps on even the most demanding games. add in a second and your up to 60 which is the ideal for that screen.
this is why i say the cards aint there yet.

also whats the point of 150 fps if your screen can only display 60 fps? you are basically gonna throw away over half of your fps on torn and dumped frames. which is again a waste of money. 2 high end gpus is where its at mate any more than that your just wasting electric for bragging rights...

 
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