Benchmarks, Power, Efficiency And Overclocking
Because we test with Intel’s default CPU multiplier and power settings (disabling any Turbo Boost multiplier enhancements), the only way for a motherboard to claim a major win is by covert overclocking, which we don’t endorse since we prefer to set our own overclocks. The only way for a motherboard to fall noticeably behind the pack is if something is misconfigured.
Investigating a covert overclock or configuration difference can be quite time consuming, so we’re happy to see ASRock’s Z97M-ITX/ac and MSI’s Z97I AC nearly tied in 3DMark, PCMark and SiSoftware’s Sandra.
The only way to game our system a little without cheating is to tighten secondary and tertiary memory timings, which often has a negative impact on stability and a positive impact on both memory bandwidth and Sandra's Cryptography module. With no major differences found between these two motherboards, we don’t need any long-winded analysis.
ASRock's Z97M-ITX/ac takes small leads across our gaming benchmarks, which doesn’t make sense when the graphics card remains consistent across platforms. Could this be due to software overhead? Disabled power-saving modes? Overclocking?
After checking to make sure that the CPU was indeed running at 4.2 to 4.4GHz (rather than locked at 4.4GHz through a motherboard-imposed setting), I decided to see if the power numbers showed anything. But first, the rest of the benchmarks!
ASRock’s Z97M-ITX/ac leads by one second in about one-third of the timed benchmarks. We normally discount leads that small due to rounding up or down, but this many leads pique our curiosity.
Will the power numbers reveal anything?
Power, Heat And Efficiency
Rather than indicating any cheating by ASRock, the power consumption numbers appear to show MSI’s Z97I AC setting power limits. Those kind of restrictions would also prevent the CPU from maintaining 4.2GHz under extra-heavy four-core loads, such as the Prime95 AVX test shown.
The math for these power limits actually works in MSI’s favor when it comes to efficiency, as the Z97I AC consumes 3.6% less power while generating 0.3% lower performance than the average of both boards. That’s a 3.4% efficiency gain over the average, and a more noteworthy 6.8% gain over the Z97M-ITX/ac it was competing against.
The Z97I AC isn't only more efficient. It also has a far cooler transistor group on its power regulator thanks to the inclusion of a small heat sink. This allows it to sustain slightly higher voltage levels, which in turn allow better overclocking.
Neither of the boards are able to reach the 4.6GHz expected of top samples because neither one could output enough current to support our 1.28V limit. At least MSI’s Z97I AC is able to support our processor’s two-thread-rated 4.4GHz with four or more threads active. That’s essentially what “Enhanced” turbo ratios are, and lots of non-overclockers enable them.