Bottleneck?

[Footyslayer]

Hi all,

my friend is slowly upgrading his PC but has done it a bit back to front, he has just got a superflower 850w PSU and an AMD 7990. Trying to play FIFA 15 it lags like hell and BF4 won't even boot up.

Now he has a Gigabyte GA-MA790X motherboard and a AMD Phenom 2 x4 920 running at 2.8ghz.

That motherboard and CPU are very old, could that be whats causing the issue here? BF4 ran on this system with a Radeon 4870, obviously that was fine for that CPU.

Is the 7990 too powerful and is causing gaming issues?

 

[trickynickyuk]

I would imagine the CPU would be causing a bottleneck instead of running it crossfire have you tried with just the 1 gpu to see if it helps performance any

 

[Footyslayer]

The 7990 is the only card being used, which is a dual GPU card. The 4870 is what he used to use and it worked with that CPU, the 7990 seems to struggle with lag in a few games. I am just trying to work out if the CPU is causing this because its not very compatable with the 7990?

 

[opethdisciple]

The cpu is a bit underpowered and wont release the 7990's power in certain games. But causing games to not start? No. Must be another problem.

 

[pandem0nium]

It could be either the 7990 or the psu.

What could be happening is the psu is failing to provide enough juice for the card when it switches to 3d clocks.

The only easy way to test would be to borrow a known working high rated psu to test. Maybe you could return both to the etailer to test them.

Don't use any adapters for the 8 pin connectors.

 

[arc@css]

Motherboard bios update?

 

[Jamielicious]

The PSU is already one of the best out there so I can't see that being an issue.

It's probably a compatibility issue with the motherboard. The fact it is PCI-E 2.0 may be a factor as well.

 

[pandem0nium]

Even the highest quality PSUs can have problems. I've had to return a Seasonic built (XFX) PSU before for example.

Edit: and there should never be an issue running a PCIe 3.0 card in a PCIe 2.0 slot. In fact I'm running a 7990 in a 2.0 slot now and have been for ages.

Updating the MB bios can sort out issues with graphics cards though, so worth a try.

 

[Footyslayer]

Off the top of my head the motherboard BIOS is updated, there has been no new release BIOS wise for years!

The PSU arrived on Monday and is brand new...

http://www.overclockers.co.uk/showproduct.php?prodid=CA-019-SF&groupid=701&catid=123&subcat=2466

BF4 does boot up now that was a different issue, however FIFA 15 is really, really laggy and is unplayable.

Any other idea's?

*EDIT*

Just had a thought, he is using 8GB DDR2 at the minute prior to a motherboard and CPU upgrade, possible issue here also?

 

[Footyslayer]

Any other suggestions please?

 

[SPArton]

Double check the BIOS version, if "off the top of your head" is wrong then you might be in for an update! However if you know there isn't an update then I guess leave it.

Check CPU and GPU usage during the game, and if the CPU is at 100% and the GPU(s) are at lower percentages, then you know where the problem is.