Supermicro C9Z490-PGW Motherboard Review: Comet Lake with 32 CPU PCIe Lanes

Board Features

The Supermicro C9Z490-PGW is an ATX motherboard with a premium controller set, with the inclusion of a Broadcom PEX8747 PLX chip. The PLX chip allows for muxing which means the four full-length PCIe 3.0 slots which can operate at x16/x0/x16/x0 or x8/x8/x8/x8, with the 16 lanes from the CPU essentially doubled up (peak bandwidth is still limited to 16x upstream). It also includes a PCIe 3.0 x1 slot, as well as a pair of PCIe 3.0/SATA M.2 slots and four SATA ports with support for RAID 0, 1, 5, and 10 arrays. The C9Z490-PGW can officially accommodate DDR4-4000 UDIMM memory, with a maximum capacity of up to 128 GB supported across four memory slots. For cooling, the board includes six 4-pin headers, with two for CPU fans, three for chassis fans, and one dedicated to water pumps.

The rear panel for a premium Z490 model is one of the most scarce for USB we have seen, with one USB 3.2 G2x2 Type-C, two USB 3.2 G2 Type-A, and two USB 3.2 G1 Type-A ports. Users can add another single USB 3.2 G2 Type-C port, two USB 3.2 G1 Type-A, and four USB 2.0 ports through the use of internal headers. It includes two video outputs consisting of a DisplayPort 1.4 and HDMI 2.0a output, with five 3.5 mm audio jacks and S/PDIF optical output powered by a Realtek ALC1220 HD audio codec. The C9Z490-PGW includes an Intel AX201 Wi-Fi 6 interface, which is the only difference between the slightly cheaper C9Z490-PG model. Wired networking includes a premium Aquantia AQC107 10 GbE controller, as well as an Intel I219-V Gigabit PHY. 

Test Bed

As per our testing policy, we take a high-end CPU suitable for the motherboard that was released during the socket’s initial launch and equip the system with a suitable amount of memory running at the processor maximum supported frequency. This is also typically run at JEDEC subtimings where possible. It is noted that some users are not keen on this policy, stating that sometimes the maximum supported frequency is quite low, or faster memory is available at a similar price, or that the JEDEC speeds can be prohibitive for performance. While these comments make sense, ultimately very few users apply memory profiles (either XMP or other) as they require interaction with the BIOS, and most users will fall back on JEDEC supported speeds - this includes home users as well as industry who might want to shave off a cent or two from the cost or stay within the margins set by the manufacturer. Where possible, we will extend out testing to include faster memory modules either at the same time as the review or a later date.

Readers of our motherboard review section will have noted the trend in modern motherboards to implement a form of MultiCore Enhancement / Acceleration / Turbo (read our report here) on their motherboards. This does several things, including better benchmark results at stock settings (not entirely needed if overclocking is an end-user goal) at the expense of heat and temperature. It also gives, in essence, an automatic overclock which may be against what the user wants. Our testing methodology is ‘out-of-the-box’, with the latest public BIOS installed and XMP enabled, and thus subject to the whims of this feature. It is ultimately up to the motherboard manufacturer to take this risk – and manufacturers taking risks in the setup is something they do on every product (think C-state settings, USB priority, DPC Latency / monitoring priority, overriding memory sub-timings at JEDEC). Processor speed change is part of that risk, and ultimately if no overclocking is planned, some motherboards will affect how fast that shiny new processor goes and can be an important factor in the system build.

Hardware Providers for CPU and Motherboard Reviews
Sapphire RX 460 Nitro	MSI GTX 1080 Gaming X OC	Crucial MX200 + MX500 SSDs	Corsair AX860i + AX1200i PSUs
G.Skill RipjawsV, SniperX, FlareX	Crucial Ballistix DDR4	Silverstone Coolers	Noctua Coolers