CrossFireX Radeon 7770 VaporX performance

[SGAN]

Hello, I'm opening this post because I have a question. It's always said that for Crossfire to work well, you need to have cards that support Crossfire x16/x16, or at least x8/x8…

But they are not worth it in x16/x4, or in x8/x4...

I'm asking this question because of the following: I just bought 2 Radeon 7770 VaporX for 2 computers... and since I was already at it, I decided to take the opportunity to test them a little in CrossFireX on one of the computers...

CPU: AMD PhenomII 965 (x4) @3.7Ghz (3.699Mhz)
Cooler: Thermaltake Frío
Motherboard: ASRock A770DE Chipset AMD 770 + SB700
Memory: 4GB (2x2) DDR2 1066Mhz Kingston HyperX
Hard Drive(s): 1TB SATA + 40GB 5400rpm ATA
Graphics: CrossFireX Sapphire Radeon 7770 VaporX
Sound: Sound Blaster Audigy 2 ZS
Power Supply: Nox Urano 700w
Operating System: Microsoft Windows 7 Ultimate

!

I tested the Crysis Benchmark, and these are the results.

Play Time: 42.75s, Average FPS: 46.79
Min FPS: 27.39 at frame 1952, Max FPS: 68.96 at frame 116
Average Tri/Sec: -30261656, Tri/Frame: -646822
Recorded/Played Tris ratio: -1.42

I don't know if they are bad or good… so I started looking around on the internet, and I found this, a CrossFire of 6850s, which are supposedly graphics cards that, although they consume a bit more, I think they perform better than the 7770s, at least in theory:

The test rig, apparently, is as follows:

CPU: AMD Phenom II (X4) 965 Processor @3913 Mhz
Motherboard:?
Memory: 7.96 GB (doesn't specify anything)
Graphics: CrossFire HD 6850
Operating System: Microsoft Windows 7 Ultimate

I see the summary of the result, but looking at the FPS during the test, it must have a similar result to mine, or even lower…

So, is the chipset and PCIe really noticeable in the performance of CrossFireX? Is my rig giving an acceptable performance despite the limitations of the PCIe and chipset?

Remember that the AMD 770, the chipset on my motherboard, doesn't officially support CrossFireX, but ASRock is a specialist in making "monstrous" things far from the usual (AGP+PCIe, DDR+DDR2, CrossFire with chipsets that theoretically don't support it, etc)

Thanks in advance, I appreciate any comments.

EDIT

I forgot to tell you how the benchmark was configured:

26/12/2012 17:51:59 - 64-bit
Beginning Run #1 on Map-island, Demo-benchmark_gpu
DX10 1920x1080, AA=16xQ, Vsync=Disabled, 32 bit test, FullScreen
Demo Loops=3, Time Of Day= 9
Global Game Quality: VeryHigh

[SGAN]

Another benchmark (I only find 6850 in Crysis 1, which is the benchmark I have right now), only gives me an Average FPS which is what is seen.

EDITO

http://www.techpowerup.com/reviews/HIS/HD_7750_7770_CrossFire/9.html

I don't understand my CFx of 7770 (temporary), it gives more than that in 1920x1080… and with AA 16xQ

Greetings.