ASRock Z77 Extreme6 Review: Legacy Bites Back

USB Speed

For this benchmark, we run CrystalDiskMark to determine the ideal sequential read and write speeds for the USB port using our 240 GB OCZ Vertex3 SSD with a SATA 6 Gbps to USB 3.0 converter.  Then we transfer a set size of files from the SSD to the USB drive using DiskBench, which monitors the time taken to transfer.  The files transferred are a 1.52 GB set of 2867 files across 320 folders – 95% of these files are small typical website files, and the rest (90% of the size) are the videos used in the Sorenson Squeeze test. 

During USB 2.0 reading, it seems that ASRock have a slightly different setting enabled or have missed a trick with optimization - they are consistently 3% slower than any other manufacturer.  This filters through a little to our real-world copy test.  As always, the advantage of ASRock XFast makes that single USB port faster than any other standard USB port on the default protocols.

Similarly, with USB 3.0 on the chipset ports, the Z77 Extreme6 does nothing spectacular, joining the other ASRock boards at the bottom end of our copy test.  Again, XFast pulls the ASRock above the default settings of other boards.

SATA Testing

We also use CrystalDiskMark for SATA port testing on a C300 drive.  The sequential test (incompressible data) is run at the 5 x 1000 MB level.  This test probes the efficiency of the data delivery system between the chipset and the drive, or in the case of additional SATA ports provided by a third party controller, the efficiency between the controller, the chipset and the drive.

Nothing special for SATA ports, as it seems that the drive is our limiting factor.

DPC Latency

Deferred Procedure Call latency is a way in which Windows handles interrupt servicing.  In order to wait for a processor to acknowledge the request, the system will queue all interrupt requests by priority.  Critical interrupts will be handled as soon as possible, whereas lesser priority requests, such as audio, will be further down the line.  So if the audio device requires data, it will have to wait until the request is processed before the buffer is filled.  If the device drivers of higher priority components in a system are poorly implemented, this can cause delays in request scheduling and process time, resulting in an empty audio buffer – this leads to characteristic audible pauses, pops and clicks.  Having a bigger buffer and correctly implemented system drivers obviously helps in this regard.  The DPC latency checker measures how much time is processing DPCs from driver invocation – the lower the value will result in better audio transfer at smaller buffer sizes.  Results are measured in microseconds and taken as the peak latency while cycling through a series of short HD videos - under 500 microseconds usually gets the green light, but the lower the better.

The ASRock Z77 Extreme6 does well in our DPC test, with only 106 microseconds.  Anything over 500 is bad, and under 200 is good.  Ivy Bridge and Z77 in this regard has set a new bar for other chipsets to follow.