The Asrock P55 Extreme4 offers perhaps the best feature set of any Intel P55 motherboard at a relatively affordable price of $150. That's roughly the same as the P55 Deluxe3 only this board carries a pair of front USB 3.0 ports and two extra on-board SATA 6Gb/s connectors. Firewire support has been dropped from the menu, though we feel this is not something the average user will miss greatly. Those that specifically want Firewire support (or eSATA which this motherboard does have) should narrow down their options to motherboards carrying those particular features.
Although the Asrock P55 Extreme4 performed much like any P55 motherboard when paired with the ever popular Intel Core i5 750 processor, results were a bit underwhelming in a couple of tests. The P55 Extreme4's auto-overclocking tools failed to work, whereas using the P55 Deluxe3 we were able to jump from the stock 2.66GHz frequency to 4.0GHz in no time using the easy overclocking BIOS feature. Shortly after we completed testing for this review Asrock released a newer BIOS revision which we haven't tested yet and might improve overclocking results.
We were interested about testing the USB 3.0 aspect of the P55 Extreme4. Keeping in mind that for now we only have a single high-speed USB 3.0 device, we were not able to load up all four ports. Still, our test was sufficient to reveal another weakness of Asrock's latest motherboard.
The Gigabyte board we used for comparison uses the PCI Express 2.0 x8 bus when it can to ensure maximum bandwidth. Asrock's USB 3.0 implementation on the other hand is limited to PCIe 2.0 x1 bandwidth, and as we found in our tests this had a noticeable adverse effect on performance -- the P55 Extreme4 was around 30% slower transferring data.
High-speed USB 3.0 SSDs such as the OCZ Enyo cost a small fortune and are far and few between, but it's still rather disappointing that this motherboard can't handle its full potential. Perhaps most importantly, USB 3.0 transfer rates were good enough for boosting the performance of a traditional hard drive, which are severely limited when used externally via USB 2.0. Overall you'd be going from 20MB/s to around 60MB/s using an external HDD, still a much welcomed improvement.
We really liked the set of features offered by the P55 Extreme4 and the board design used by Asrock, however there a few question marks remain over this product when it comes to value. It costs a symbolic $5 less than the P55 Deluxe3 and brings an extra pair of USB 3.0 ports which are accessible from the front. But unless you intend to run your processor at stock frequencies and don't mind the USB 3.0 bandwidth limitation, picking this motherboard doesn't seem like the best investment.