AMD’s FX-8150 and CrossFire Scaling – Bulldozer Part 2, the Conclusion

FX-8150 Performance in 20 games

Here are the summary charts of our 20 games and 3 synthetic tests. CPU core speeds are shown in GHz. All results except for Vantage and 3DMark11 show average framerates and higher is always better. In-game settings are fully maxed-out and they are identical across all platforms except for Left 4 Dead where the Intel CPU uses a slightly different benchmark from the AMD CPUs (Steam updated the game during the testing).

We remember stating that CrossFire Scaling was so bad on the stock-clocked FX-8150 that we were inclined to suspect driver issues instead of the CPU hitting any “wall” as some other sites have suggested. And indeed, we see even with the overclocked FX-8150 where clearly scaling has returned, there are some definite issues with CrossFire-X2 and especially Tri-Fire-X3 in some games.

However, we start to see a normalcy return to CrossFire scaling as we increase the core speed of our FX-8150 from 3.6GHz to 4.4GHz and it again generally surpasses the 4.3GHz Phenom II just as it did with HD 6970. For FX-8150 to become really competitive with very fast graphics, it really needs to be overclocked to shine – especially in CPU performance-limited games.

Summary Charts

We are repeating the charts from Part One with the addition of HD 6990 overclocked to HD 6970 CrossFire performance and speeds. Note that in most cases, the difference between overclocked HD 6990 and HD 6970 CrossFire performance is within the margin of error; any other differences can be attributed to drivers and/or possibly different vRAM timings. And now we are testing our HD 6990 with our FX-8150 at 3.6GHz and at 4.4GHz. In addition, we added a third GPU for 3 x HD 6970-X3 Tri-Fire performance to see if we could still get further scaling with the third GPU at stock FX-8150 speeds and what effect overclocking it a further +800MHz does for performance

These charts are getting pretty wide, so it is suggested that you click on them and open them in another window or tab. And following the Summary charts are 4 really long graphs for those who want to visualize the numbers.

First, here are the expanded summary charts:

Now here are the same charts expressed in graphs. First up is the HD 6970 with our CPU platforms in two long halves of a chart:

We see the FX-8150 generally does quite well in gaming with a powerful single-GPU video card. There is generally not a lot of difference between our stock clocked and our overclocked FX-8150 with a single HD 6970. And now we look at the graphs of HD 6970-X2 CrossFire which is generally equal in performance to our HD 6990 at 880/1375MHz.

We run CrossFire-X2 and X3 with our FX-8150 both at stock clocks and at 4.4GHz. Note the HD 6970-X3 Tri-Fire scaling results with both the stock and overclocked FX-8150 over the X2 configuration. It now makes quite a difference to overclock the FX-8150!

As we have seen before, it requires overclocking the Phenom II 980 BE to approximately 4.3GHz to match the Intel i7-920 at 3.8GHz (with Intel’s Turbo Boost on to 4.0GHz on a single core) in relatively high-end gaming. And the FX-8150 at stock 3.6GHz (with Turbo Core rarely turning on in gaming) generally does well in most of the benches, winning the most of any platform for the single-GPU HD 6970. And overclocking it further to 4.4GHz makes it the clear winner in most cases. However, the picture changes dramatically with CrossFire scaling and the AM3+ platform with the FX-8150 at stock clocks.

Besides poor scaling at stock with FX-8150, we also see some issues with drivers and especially CrossFire-X3 scaling. However, in the games that do scale, it usually makes a notable performance difference to overclock the FX-8150. We see that the architecture is sufficient to scale to match increasing faster graphics up to HD 6970-X3 TriFire.

Of course, we want to explore this further with HD 6970-X4 Quad-Fire scaling and a further overclock of our FX-8150 as we water-cool it hopefully to beyond 4.6GHz. Expect further evaluations featuring the FX-8150 and also GTX 580 and GTX 580 SLI in our upcoming “CrossFire vs. SLI, Part 2 – High-End Multi-GPU Scaling” which is the continuation of a series.