CrossFire R9 390's Cpu i5 4690k Bottleneck

[DennDeDennDenn]

Hello all i just got my second r9 390 graphics card but when i enable Crossfire it uses both gpu's but with half power (700~ Mhz) and i get stuttered gameplays. This is with Dying Light Gta 5 and Tomb Raider , Im playing on a 1440P screen and Cpu uses hovers around 90 and sometimes jump onto 100% but i've read somem forums and they say the the i5 4690k shouldnt be bottlenecking anything so im kinda confused Help me please .

Gpu: 2x Sapphire R9 390
Cpu: i5 4690K (OC to 4.00)
PSU: 850 Watt

 

[PP Mguire]

Already answered your question which you thanked the post for. If you're still using the same board you're going to have the same problem.

http://www.techist.com/forums/f75/problem-sapphire-r9-390-crossfire-277699/#post2180282

 

[DennDeDennDenn]

Hi , I got the MSI gaming 5 motherboard , wich does support crossfire , I had a 4k monitor when using crossfire and had no stutters or something , had low fps 50~ (ish) but still it worked , now i switched monitors , so from 4k to 1440p and my crossfire setup suddenly doesnt work how it used to work , my cpu hovers around 90-95% when playing games (wich is the bottleneck) but why does my cpu bottleneck the GPU on 1440p when 4k res should ask for more , i dont understand

 

[PP Mguire]

Firstly, you have your cards in the first and second 16x slots, correct?

What games are you playing, and what is your GPU usage when playing these games? Just because your CPU usage is high doesn't mean it's a bottleneck.

 

[DennDeDennDenn]

Pci E x16 yes , I have turned off Crossfire now cause gaming without it goes smoother than with it ,

I am playing Battlefield 4 , Gta 5 , Dying Light , And my Gpu usage is 99~100% most of the time giving me everything , but when i enable Crossfire then both of the card give 700~ ish sometimes less i gues they both working towards the 1100mhz wich my card is OC'd at

 

[PP Mguire]

Since you've done the board change have you flushed your drivers and reinstalled new ones?

It sounds like your cards GPU usage is dropping so they are ramping down due to less utilization. This could be one of two things, drivers or power.

 

[DennDeDennDenn]

But how can this suddenly change when all i did was change the monitor , @ 4k resolution they both were @ 100%~ ish and i didnt change anything besides the monitor , 4k>1440P.

My PSU is 850 Watts wich was enough for 4k so i can gues its also good enough for 1440p,
Is there anything else what could be the problem ?

Asus mg278 Gaming monitor is what i changed it with 144HZ and im using displayport cable with it.

 

[PP Mguire]

What FPS are you getting in these titles @ 1440?

I said power because your cards take 300 watts a pop and your CPU since it's OCd another 100w or thereabouts. Theoretically the CX850 should handle it, but it's still a budget PSU and as such could be drooping. No real way to know for sure unless some testing was done.

Changing the monitor could do it. Go into uhhh what is AMD's driver suite called now? Crimson? Go into there and make sure your refresh rates are set to 144 and not 60. Also in game. Another thing you can do is use 3dmark Firestrike or Unigine Heaven which if all is well should load the cards to 100% and we can monitor what's going on there. That monitor supports Free-sync which would also be doing it messing with your refresh causing your cards to not need to work as hard.

 

[DennDeDennDenn]

Hi , i just ran Heaven Benchmark and got 88 FPS @ 1440P @ ULTRA And both card were running 99-100% with both using full power 1040 MHZ (except tesselation wich was @ normal) I normally run these games @ 60+++ Fps.

One card gives me 60+ fps (wich is fine) but when i use crossfire it DOES give me MORE FPS but stutters enormusly, Using 50% on both card or using 700~ of its 1040 MHZ.

 

[PP Mguire]

And it does this on every single game or just one?

I was trying to get a hard figure of FPS these games are giving running both cards. If it's hitting a cap due to freesync or vsync this will happen.