ASRock 890FX Deluxe: Comprehensive Motherboard Review & Investigation of Thuban Performance Scaling

We are splitting today’s test into two parts.  In part one; we take a look at the impact of Thuban’s CPU-NB (or IMC, integrated Memory Controller) on performance, courtesy of our retail 1090T and the ASRock 890FX Deluxe 4.  In part two we’re pitting the ASRock 890FX Deluxe 4 against ASUS’ M4A89GTD Pro/USB3 through our usual but slightly revised and condensed benchmark suit.

For the latter, we would like to ask readers ahead for an understanding that this is our first evaluation of the 890FX-based board and we are in the middle of devising a proper testing suit for this platform.  Once we have more experience with products based on this chipset, we will have a thorough comparison of power consumption and onboard controllers, including multi-GPU performance.

To make up for this deficit, we decided to spend some time on investigating the new CPU-NB of Thuban.   It is a well-known secret that Phenom architecture benefits from faster CPU-NB.  The bottlenecks are manifold, but we hypothesize a few.

1. The CPU-NB’s frequency is directly responsible for the transaction of data between CPU and memory.  Lower CPU-NB frequency thus tends to waste memory bandwidth.
2. The CPU-NB’s frequency is also the CPU’s L3 cache frequency.  Even when memory access doesn’t come into equation, slow L3 impacts the overall CPU performance.
3. The CPU-NB is what controls the memory  (it’s another name is “IMC” after all). A higher quality IMC tends to be more flexible when it comes to DIMM frequency and timings.   Whether overclocked or not, previous generation Phenoms didn’t like high speed memory, even though the same modules were perfectly able on Intel platforms.

Assuming the above, it is easy to imagine the performance impact CPU-NB plays on this architecture. Any of the above can present a performance bottleneck.  Prior to E0 revision silicon (Thuban is E0 stepping), Phenom II’s CPU-NB’s quality was frankly abysmal, and outside extreme conditions (i.e. sub-zero) there just wasn’t enough room to improve performance by manipulating CPU-NB.

However, we now see a dramatically different characteristic of the CPU-NB in E0 silicon Thuban CPUs.  Previously unthinkable frequencies under air-cooling are now a possibility, and it handles high frequency DIMMs much better as well.  So we think it is a perfect time to start examining the impact of the CPU-NB in AMD’s “Star” architecture.