Machinist X99 RS9: Full Review

The X99‑RS9 is one of Machinist’s oldest boards, with the first version dating back to 2020. Since then, several new revisions have been released, and the board has earned a reputation as a budget‑friendly yet fairly reliable model.

In 2025 the board received a major update — a new revision with an 8‑phase power delivery is now available.

Specifications

The board uses a typical black‑and‑red color scheme and looks quite attractive. It’s built on desktop chipsets — B85 or Q87 — and C226 can also be found. Regardless of chipset, the feature set does not change.

The RS9 offers quad‑channel memory mode, a sufficient number of ports, and decent overall quality. Highlights include four fan headers, a POST code display, and an M.2 Wi‑Fi slot.

The power delivery is classic budget fare: 3 doubled phases (6 effective), each with two MOSFETs. MOSFET choices vary by revision, but most often you’ll see SM4522NHKP (110 A / 2.65 mΩ; ×6, low‑side) and SM4508NHKP (48 A / 6.8 mΩ; ×6, high‑side) MOSFETs, the uP1649Q PWM controller common on Chinese boards, and uP1961S MOSFET drivers (×3). This configuration was common in 2020–2022, but it looks a bit weak today — especially now that low‑cost boards with 8‑phase VRMs have appeared.

Speaking of drawbacks, we should mention the usual rough edges found on most Chinese LGA2011‑3 boards:

Common Limitations of Budget Chinese X99 Motherboards:

Temperature Monitoring Issues

Temperature monitoring doesn’t work properly on most budget Chinese X99 boards. Onboard sensors are non-functional and display erratic readings (such as 120°C+ in monitoring software like AIDA64) due to faulty sensor implementation. However, CPU temperature monitoring via the processor’s built-in sensors remains accurate.

Limited Fan Control

Fan control only works with 4-pin PWM CPU coolers. 3-pin case fans run at constant speeds without automatic regulation. Consider using manual fan controllers or PWM adapters as workarounds.

BIOS Limitations

The BIOS implementation is often incomplete. You’ll find numerous settings and options, but many simply don’t function as intended or have no actual effect on system behavior.

Most critically, memory timing controls are hidden in the stock BIOS. This prevents manual RAM overclocking and fine-tuning. However, you can solve this by flashing modified BIOS versions that unlock these hidden advanced memory timing options and other concealed features.

AIDA64 Freezing

Chinese boards with desktop chipsets (H81, B85, Q87, etc.) have broken motherboard temperature sensors that freeze AIDA64.

Fix: Disable the faulty sensor in AIDA64

• Enable status bar: View → Status Bar
• Right-click the status bar at the bottom → HWMon Modules → uncheck PCH / Bibxy
• If this doesn’t help – disable all sensors and enable them one by one to identify the culprit.

Revisions

6‑phase revisions

Over its lifetime, the classic X99‑RS9 has received at least five revisions: rev 1.0; rev 1.11; rev 2.0; rev 3.0; and rev 3.1. Unfortunately, the manufacturer doesn’t keep a changelog, and the revision numbers don’t seem to follow a clear logic. What’s more, you may see one revision number on the PCB, another on the sticker on the back, and yet another in the BIOS. All this left us thoroughly confused, so we decided to generalize our experience with the different versions of this motherboard.

By and large, all revisions are similar and differ only in details: the audio codec, the BIOS chip, and the presence of a POST code display. The most important difference we found is that some versions ship with a slightly different power stage: revision 2.0 uses Niko‑Sem MOSFETs instead of the more common Sinopower parts.

As a result, there’s no significant difference among the various 6‑phase Machinist X99‑RS9 versions. In most cases, firmware from different revisions is also interchangeable.

A note on TPM 2.0. There’s no dedicated TPM 2.0 header on the board, but there is a JLPC1 header through which custom TPM 2.0 modules can be connected. You’ll need the module itself and, possibly, third‑party BIOS firmware that supports it. More information about such modules can be found here.

8‑phase revision (X99RS9 v1.21)

This revision was introduced in 2025 and has not yet been tested. The board gets an 8‑phase VRM (4 virtual phases with doublers; two MOSFETs per phase) and active cooling. The storage subsystem has changed, and other changes are possible as well.

We don’t yet have complete data on the board’s specs or its BIOS. This article will be updated after testing.

BIOS Capabilities

There are quite a few stock firmware variants, but they’re similar and share the same shortcomings: no access to RAM timings, no way to overclock unlocked CPUs, and broken power/temperature sensors.

Fortunately, most of these shortcomings can be fixed by flashing BIOS images from third‑party vendors or other Chinese boards (100% compatibility is not guaranteed; proceed with caution).

At the moment we don’t have firmware for the 8‑phase revision, and we’re not aware of its compatibility with firmware for older revisions.

Simple BIOS Flashing Guide (Windows)