Using the Maya test from SPECviewperf v10 we see that the Gigabyte 870A-UD3 leads the Asrock 880GMH/USB3 by a considerable margin while it was also faster than the MSI 870A-G54. Worth noting that the Gigabyte 870A-UD3 paired with the unlocked Phenom II X2 555 was actually faster than the Phenom II X6 1090T in this test.
Again we find that the affordable Phenom II X4 555 is able to match the Phenom II X6 1090T when unlocked. This time when testing with Povray 3.6 all three budget AM3 motherboards defeated the six-core Phenom II X6 1090T configuration.
The OpenGL test from CINEBENCH R11.5 appears to favor the AMD configurations as all are found to be faster than the Core i5 750. While the Phenom II X6 1090T came out on top it was only a fraction faster than the unlocked Phenom II X2 555 configurations.
CINEBENCH R11.5 was used to measure CPU performance and as you can see the quad-core configurations delivered roughly the same performance while the Phenom II X6 1090T had a natural advantage in this test.