R9 290 crossfire with Core i7 920 @ 3.8GHZ

[jyeung80]

Hi guys,

I've just purchased 2 x Gigabyte R9 290 Windforce Edition graphics cards and am running them with my old Core i7 920 which is currently clocked at 3.8GHZ. I'm using a Gigabyte EX58-UD4P motherboard. The 290's are in both the PCIE 2.0 x16 slots. My monitor resolution is 2560x1600, I have a 1000W PSU and 6GB RAM and am using the latest stable 14.4 Catalyst drivers.

I've read that neither the PCIE 2.0 or i7 920 should be a bottleneck for these graphics cards. However, when I run the inbuilt benchmark in Tomb Raider using the "Ultimate" settings preset, I'm only getting an average of about 45fps. According to most reviews, I should be getting much higher.

Any idea what might be causing the bottleneck? I'm thinking it's either the CPU, motherboard, or the top GPU throttling as it doesn't get a lot of room to breathe...

Thanks.

 

[Nuckles_56]

Can you give us CPU usage figures when the benchmark is running?

 

[jyeung80]

The CPU usage never went above 46.5% and physical memory usage never went above 58% so I think I can rule out CPU or RAM as the bottleneck. I'm pretty sure it's the second GPU overheating and throttling because it doesn't have enough room to breathe. The logs showed that it hit 94 C even though the fan speed was at 100%. From there I can see the clock speed drop back slowly.

The other thing that made a huge difference (although I'm not sure why) was that I uninstalled the 14.4 drivers because I was getting some random BDOD's and have installed the 14.7 beta drivers. With the new drivers, before the throttling starts, I can get well over 100 fps with an average fps somewhere in the 70's which is much more in line with what I've seen in the reviews. Once the throttling starts, all bets are off.

Unfortunately, there's not much I can do with the placement of the second card. I do have a third PCIE slot but it's only PCIE 2.0 x8 which wouldn't be so bad, but it's at the bottom of the motherboard and my case (Antec 1200) doesn't support dual slot cards in the bottom PCIE slot - I'd have to cut a hole in the case which I don't have the tools to do. Maybe I'll use this as an excuse to upgrade

 

[Nuckles_56]

Yeah, I guess we can safely say that it is you GPU getting too hot and throttling which is causing your fps issues, so I guess the new case is going to be worth the money then, either that or a full system upgrade but that is up to you, if you do want that, I am more than happy to give you some suggestions.