Skip to main content

ASRock X99 Extreme6/ac Motherboard Review

Featuring the same wireless controller as its closest competitor, ASRock’s X99 Pro adds a second gigabit Ethernet controller and removes a few pathway sharing issues. Have we finally found a value-winning solution for high-end LGA 2011-v3 buyers?

Results: Performance, Power, Efficiency And Overclocking

Massive integration of platform components into our favorite processors limits the value of most benchmarks to verification, since there are far fewer settings an individual motherboard manufacturer can play with (without blatant overclocking, which destroys an apples-to-apples comparison).

3DMark and PCMark

Image 1 of 3

Image 2 of 3

Image 3 of 3

3DMark and PCMark show that the X99 Extreme6/ac has no performance problems, and no obvious signs of out-of-spec overclocking.

SiSoftware Sandra

Image 1 of 4

Image 2 of 4

Image 3 of 4

Image 4 of 4

Motherboard manufacturers have a little more flexibility when it comes to memory tuning, but the X99 Extreme6/ac is essentially matched to the top three boards in this comparison. Gigabyte’s X99-UD4 fell slightly behind in September, though that small difference might have already been addressed via firmware updates. We’ll check the next Gigabyte sample to see how the company’s BIOS engineers have progressed.

3D Games

Image 1 of 4

Image 2 of 4

Image 3 of 4

Image 4 of 4

An unusual lead in Grid 2 and loss in Arma 3 makes us glad that we’re using the average of several games to rate the X99 Extreme6/ac’s performance.

Non-Gaming Applications

Image 1 of 4

Image 2 of 4

Image 3 of 4

Image 4 of 4

The X99 Extreme6/ac’s better-than-average completion time in 7-Zip file compression is offset by a slightly longer-than-average time in WinRAR. This same motherboard appears roughly average in A/V encoding, Creativity and Productivity.

Power And Efficiency

Image 1 of 4

Image 2 of 4

Image 3 of 4

Image 4 of 4

The X99 Extreme6/ac consumes a surprisingly small amount of energy under Prime95, but then again so did its cheaper Extreme4 sibling. Comparing its 99.8%-of-average performance ranking to its 95.4%-of-average energy consumption, we find 4.7% above-average efficiency. That is, in spite of its installed (and active) Wi-Fi controller.

Overclocking

ASRock X99 Extreme6/ac
BIOS Version1.40 (11/11/2014)PCH Voltage0.90-1.50V (25 mV)
Base Clock96-300 MHz (0.1 MHz)DRAM Voltage1.00-1.80V (10 mV)
CPU Multiplier12-120x (1x)CAS Latency4-31 Cycles
DRAM Data Rates800-2666 (200/266.6 MHz)tRCD5-31 Cycles
CPU Vcore0.080-2.00V (1 mV)tRP5-31 Cycles
VCCIN1.20-2.30V (10 mV)tRAS10-63 Cycles

A quick comparison of ASRock’s X99 Extreme6/ac and X99 Extreme4 shows the benefit of a little firmware tuning. Our first batch of boards simply wouldn’t run this processor stably at the 125MHz BCLK needed to reach DDR4-3000 at Intel-validated multipliers. Asus’s X99 Pro is the reason for that long-winded description, since it’s the only board we’ve tested so far to support memory ratios exceeding Intel’s validated 10x maximum.

ASRock’s added efforts result in the X99 Extreme6/ac reaching the same 132MHz BCLK as Asus’ X99 Pro. It can’t do that without dropping the memory ratio though, as its data rate tops out at 3046MT/s. That data rate comes from a 9x DRAM ratio, a 4:3 memory controller to CPU core ratio, a 127MHz BCLK and the DDR data rate multiple of 2x. Phew!

Thomas Soderstrom
Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.