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New rig headaches!

cfcboy77

cfcboy77

cfcboy77

Associate
Joined
13 Mar 2013
Posts
39
Hey all, so my current system ive got is running pretty darn smooth and for witcher 3 lets say, ive been getting around 40fps on 4k @ high (no aa)

4690k 4.4
MSI Mate z97
Corsar Vengeance 16Gb 1600mhz
EVA supernova 850W
1TB hybrid
MSI r9 390
Phillips 4k 40" Screen

I decided (being the greedy sod that i am) to get another r9 390 and crossfire.
Uninstalled drivers, installed second card, reinstalled drivers, enabled CF .... drop down to 23fps in witcher 3 and in general every other game is a choppy mess. Alien Isolation seems pretty perfect though so thats something to go on i guess.

From then on ive tried a lot of things but still struggling. I thought it could be the mobo, one pcie is Gen 3 x16 and the other is Gen2 x4. I tried swapping the 390 into the gen2 and hardly noticed a thing, maybe a 2fps drop in intense games at most.

Driving me nuts lol, should i just jack it in and return the second card and just wait for a better single card solution. Many Thanks in advance
 
Just Googled your motherboard

I'm surprised AMD certified that as crossfire friendly! There's no way PCIE 2.0 x4 is enough bandwidth.

The 390's swap data directly over the PCIE lanes and though it might not affect one card much (2 fps you said) its just not fast enough to support decent crossfire.
 
Soo I take it there both the same make and model anx both are plugged in to the blue pcie slots only thing I can think of is power I had r9 290s not sure how good or bad the 390s are
 
that doesnt sound right, why would z97 boards have gen 2 slots ?
doesn't your board have multiple 16x gen 3 slots ? sometimes it will drop to 8/8 but thats ok, what else is plugged into the pci slots ? could it be that it is using too many lanes ?
 
Ash0787 said:
that doesnt sound right, why would z97 boards have gen 2 slots ?
doesn't your board have multiple 16x gen 3 slots ? sometimes it will drop to 8/8 but thats ok, what else is plugged into the pci slots ? could it be that it is using too many lanes ?
Click to expand...

There not the blue pcie are x16 the small black ones are x4
 
Last edited:
dreigns said:
Soo I take it there both the same make and model anx both are plugged in to the blue pcie slots only thing I can think of is power I had r9 290s not sure how good or bad the 390s are
Click to expand...

This ^
I have a R9290 and i was looking to CF at one point, i was rated ATLEAST an 850w, of a high certificate... Could be the power supply not giving enough juice? I would try for atleast 1000w, im sure you could try and send it back if no difference, however i think this, or your motherboard lane bandwidth could be the issue. If im going to be brutally honest, 850w isnt enough, and the motherboard isnt good enough to support CF, saying as you are running a 4k display and have the money to just throw at gpus and you have and expensive cpu, why not put some decent money into a motherboard and PSU.
Examples:
https://www.overclockers.co.uk/showproduct.php?prodid=MB-260-MS&groupid=701&catid=5&subcat=2811
A high end motherboard from MSI, very very good.
https://www.overclockers.co.uk/showproduct.php?prodid=CA-009-SF&groupid=701&catid=123&subcat=2465
Very good, reliable Power supply, from a brand pretty much everyone recommends on here for PSU's

Have a look into these, and they should sort your issues out, also the psu will save you money over time with the added efficiency (albeit not much but hey ho every little helps :p )
 
The motherboard:

PCI Express 3.0 x16
1 x PCIe x16 slots
PCI_E2 supports PCIe 3.0
Support x16, x4/x4 modes

PCI Express 2.0 x16
1 x PCIe x16 slots
PCI_E4 supports PCIe 2.0
Support x16, x4/x4 modes

PCI Express x1
2 x PCIe 2.0 x1 slots
PCI Slots
2 x PCI Slots


So the primary slot is PCI-E 3.0 X16
Secondary slot is PCI-E 2.0 X16

Looking at the spec, it looks like the only other option is x4/x4 mode which sucks and MAY explain his bad performance, but not guaranteed.
 
Last edited:
Thanks all for the replies. I thought it might be the psu and mobo but on Alien Isolation both GPU's are being utilised @ 100% and running perfectly. So if it was pcie / psu / mobo wouldnt other games be just as effected?
 
The chipset does not have 16 PCIe lanes to give to the 2nd GPU. The CPU only has 3.0 lanes. It cannot be, electrically, a x16 slot.

Run GPUz and see how many PCIe lanes each GPU has.

Slots

• 2 x PCIe x16 slots
- PCI_E2 supports PCIe 3.0
- PCI_E4 supports PCIe 2.0
- Support x16, x4/x4 modes

• 2 x PCIe 2.0 x1 slots
• 2 x PCI slots
Click to expand...

That's from the motherboard specs page. If the 2nd slot is not 3.0 it's because it's not coming from the CPU, meaning it is coming from the chipset. If it's doing that your datas is going over DMI2.0 to the CPU (basically PCIe 2.0 x4) and sharing DMI bandwidth with the LAN, hard drives, USB, Audio, etc etc.

This would smash performance to be honest.

This is why AMD should certify crossfire implementations like nVidia do with SLI rather than just allowing anything to work, as it leads to people wrongly getting a bad impression of crossfire.

Edit: In this pic http://imgur.com/pwVkG9q you can see there are not electrical connections along the whole length of the 2nd slot. It is not (cannot be) a x16 slot. The manual indicates it is x4, and as PCIe 2.0 x4, it is effectively PCIe 3.0 x2, and 1/8th the bandwidth of the other GPU.
 
Last edited:
rtho782 said:
The chipset does not have 16 PCIe lanes to give to the 2nd GPU. The CPU only has 3.0 lanes. It cannot be, electrically, a x16 slot.

Run GPUz and see how many PCIe lanes each GPU has.



That's from the motherboard specs page. If the 2nd slot is not 3.0 it's because it's not coming from the CPU, meaning it is coming from the chipset. If it's doing that your dats is going over DMI2.0 to the CPU (basically PCIe 2.0 x4) and sharing DMI bandwidth with the LAN, hard drives, USB, Audio, etc etc.

This would smash performance to be honest.

This is why AMD should certify crossfire implementations like nVidia do with SLI rather than just allowing anything to work, as it leads to people wrongly getting a bad impression of crossfire.

Edit: In this pic http://imgur.com/pwVkG9q you can see there are not electrical connections along the whole length of the 2nd slot. It is not (cannot be) a x16 slot. The manual indicates it is x4, and as PCIe 2.0 x4, it is effectively PCIe 3.0 x2, and 1/8th the bandwidth of the other GPU.
Click to expand...

Think about it.. would this only happen on crossfire? As i treid the gpu on the 2nd gen and ran almost the same as the gen3..
 
theaterix said:
This ^
I have a R9290 and i was looking to CF at one point, i was rated ATLEAST an 850w, of a high certificate... Could be the power supply not giving enough juice? I would try for atleast 1000w, im sure you could try and send it back if no difference, however i think this, or your motherboard lane bandwidth could be the issue. If im going to be brutally honest, 850w isnt enough, and the motherboard isnt good enough to support CF, saying as you are running a 4k display and have the money to just throw at gpus and you have and expensive cpu, why not put some decent money into a motherboard and PSU.
Examples:
https://www.overclockers.co.uk/showproduct.php?prodid=MB-260-MS&groupid=701&catid=5&subcat=2811
A high end motherboard from MSI, very very good.
https://www.overclockers.co.uk/showproduct.php?prodid=CA-009-SF&groupid=701&catid=123&subcat=2465
Very good, reliable Power supply, from a brand pretty much everyone recommends on here for PSU's

Have a look into these, and they should sort your issues out, also the psu will save you money over time with the added efficiency (albeit not much but hey ho every little helps :p )
Click to expand...

you don't need more than an 850w psu for crossfire 290x's im running them perfectly fine cpu overclocked and so are both gpu's.

problem will more than likely be the ancient X4/X4

copied from elsewhere
The x4 lanes are not delivered from the CPU like the first 16x slot is, adding latency and performance penalties.
There are threads/forums out there that can explain it in more detail, but reports that some highend setups on such 16x/4x can actually decrease performance over a single card as well as on the other hand, only giving a marginal increase but with more stuttering which 'feels' like its worse than a single card can do.

It's not just frame pacing (crossfire smoothness) being the issue, as the 4x slot is the issue, no frame pacing fix's that AMD now include in their drivers will help you.
Invest in a motherboard than can do PCIE 3.0 16x/16x or PCIE 8x8 when in crossfire/sli.
 
If I recall correctly, ain't the MSI Z97 Mate a budget entry level Z97 chipset board that's made almost specifically for cheap Pentium Anniversary build, rather than serving as a foundation for exotic high-end multiple GPU gaming build...?
 
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