Dual-CPU Server on the Cheap
Background
My first dual-CPU system was a workstation featuring two 233 MHz Pentium II Slot-1 processors. Back in 1997, running OS/2 and optimized software, it easily outperformed other systems. Ever since then, I’ve wanted another dual-CPU workstation, but for years, no chipsets appeared to support dual CPUs. Then Intel introduced the C6xx, which opened up the possibility for dual-CPU setups. However, the CPUs were Xeons, costing anywhere between $2,000 and $10,000 each at the time, and motherboards were upwards of $1,000. The CPUs I have cost $6.50 each used, but were still $6,500 each new in early 2020. They have reached their end-of-life as far as Intel goes, but many servers are being retired and salvaged, freeing up a lot of old Xeons and C612 chipsets. The Chinese designers are integrating the salvaged C612s into motherboards with single or dual CPUs.
As time passed, and those older E5 Xeons became available, the price dropped to as little as $5 each. The motherboard prices, unfortunately, didn’t follow suit. I had previously built a server using an ASRock Extreme 4 motherboard with a quad-core Xeon processor that cost me $420 in 2017, and later upgraded it to a 12-core Xeon in 2025 for just $6. After eight years of use my ASRock Extreme 4 motherboard developed memory issues, so I decided to revisit dual-CPU motherboards. That’s when I discovered the Huananzhi F8D Plus—a perfect fit for my needs at only $125.
The photograph was taken before the 2 120 mm fans were added to the top of the power supply box. You may notice by the picture that I missed one standoff by the SATA connectors. An oversight. I remembered to put it in, but then forgot. It took a while to get the motherboard installed, and I wasn't about to take it out and put it in again. The board is stiff, and doesn't flex at all.
The Dual-CPU Motherboard: Huananzhi F8D Plus
After waiting a week for the board to arrive, I found it to be DOA. Thankfully, the replacement worked perfectly. Curious about the motherboard’s “X99” name, I asked the manufacturer why it was called X99 if it didn't have an X99 chipset on it. Their response was: “It’s just the name of the board. The C612 is the same as the X99.” An odd explanation, considering the X99 chipset doesn’t support multiple CPUs, while the C612 does. This company sells motherboards for as little as $40, often salvaging C612 chipsets from old servers. As such, many of their boards are only compatible with Xeon or i7-5xxx and -6xxx CPUs using the 2011-V3 socket. The i7s don't have support for multiple CPUs.
The Xeons have 40 PCI-E lanes each, and all 80 PCI-E lanes are used for PCI-E card slots (PCI-E v3.0): three x16 slots, three x8 slots, and four lanes each for the two m.2 NVMe sockets. There’s also a third m.2 NVMe/NGFF, which uses PCI-E 2.0 and one SSATA port for NGFF. However, don't waste a good Samsung 9100 Pro in any of these sockets, as its performance will be underwhelming.
The board has eight DDR4 memory sockets supporting up to 512 GB. For optimal performance, populate all eight slots with identical capacity, CL, and clock speed. If you have six sticks, distribute them evenly—three per CPU—and set the BIOS to 1-way or 3-way interleave. I used 8x 8 GB sticks for a total of 64 GB. Since I filled all the slots, I configured the memory interleave to the highest (4-way) in the BIOS. The red memory sockets are number 0 and 1, so populate them first, if you only have four sticks.
For memory, I used CMS DDR4 2400 MHz 32 GB (4x8 GB) non-ECC DIMMs originally intended for an ASRock Z390 motherboard, as "compatible" modules for these budget boards weren’t readily available. Speaking of budget, $125 for this board is far cheaper than the nearest competitor, priced at around $500 but lacking similar features. Newegg now sells them for $237.00, shipping from China. Still a good deal, but if you want to get them from the USA, you can find them on AliExpress for $122 to $129 on sale.
Key Features
- 2x CPU 2011-3 sockets
- 6x SATA and 4x SSATA ports
- 3x PCI-E x16 slots
- 3x PCI-E x8 slots
- 2x 2.5 G Ethernet ports
- 2x NVMe (PCI-E 3.0) locations
- 1x NVMe (PCI-E 2.0) location
One thing that bears mentioning is the spacing between the CPUs, and the memory slots. They are all really close. Many 2011-3 coolers won’t fit. Noctua makes a compatible cooler available on Amazon and Newegg. At 110 mm tall, it fits, is just over the 2011-3 socket size, and has sufficient cooling capacity. The two coolers keep my CPUs' idle temp at ~27°C and full load at ~53°C. If you can find a less expensive cooler, you can save a few bucks.
Form Factor and Installation
The manufacturer/seller describes the motherboard as “standard E-ATX,” which is misleading since there’s no standard definition for E-ATX. This board is actually EEB-sized, with the mounting holes to prove it. To house this 330 mm-wide board, you’ll need a case explicitly designed to support EEB. My older case didn’t fit, so I improvised by drilling additional mounting holes. The only readily available case I found that officially supports EEB was the Montech AIR 903. It accommodates ATX, Micro-ATX, Mini-ITX, SSI-EEB, and so-called E-ATX boards (though the meaning of E-ATX varies).
For comparison, my workstation motherboard, also labeled as “E-ATX,” is only 0.6 inches wider than ATX, while this server motherboard is 2.8 inches wider. Both cannot fit the same “E-ATX” label. I’m now transitioning to smaller cases painted white for better visibility during wiring. White-on-white is much easier to see than black-on-black, especially for aging eyes. Unfortunaely, a smaller case doesn’t mean a lighter system—it still weighs the same.
The CPUs
The motherboard supports E5-26xx V3 or V4 CPUs, compatible with its 2011-v3 sockets. Both CPUs must be identical, as must the RAM configuration, ensuring uniform behavior across the system. While a few settings are configured per CPU, most, including memory interleaving, are global and must remain consistent to ensure proper functionality.
I dedicated several days to analyzing charts, benchmarks, and Intel documentation, searching for a balance where single-core performance wasn’t completely sacrificed for multi-threading capabilities. I concluded that the E5-2698 V3 represents this sweet spot. To explore further, I also acquired a pair of 14-core CPUs, providing options for 12, 14, and 16 cores to test with. While the E5-2697A V4 offers better performance with its 16 cores, 2.6 GHz clock speed, and faster execution times, each CPU costs $40. Maybe when the cost comes down I'll get a couple.
Benchmarks and Power Consumption
To measure total power consumption, I conducted benchmarks using the Blender test. For comparison, I also ran the same test on my i9-12900K, having 128 GB of RAM and an RX 6600 XT video card. The results were as follows:
- Dual 12-core Xeons: Consumed 401 watts with a benchmark score of 385.
- i9-12900K: Consumed 343 watts with a slightly better benchmark score of 405.
The i9’s performance surprised me—I expected a larger gap in scores. However, I suspect the CPU was thermal-throttling, reaching temperatures above 92°C, and then slowing down. At the time, I was using a 240mm AIO cooler. I have a 360mm AIO to better manage the heat when I rebuild the workstation. EDIT: With the new cooler the i9 gets a score of 414 and a max temperature of 50.2°C. It really was throttling.
Power measurements were taken from the AC line to account for total system consumption. For temperature, I recorded the average across all cores of both CPUs, and the peak of that average temperature achieved during the benchmark.
| Total | Average | Blender | Passmark | |||||
|---|---|---|---|---|---|---|---|---|
| CPU | Cores:Threads | Temperature | Watts | Overall | Single Thread | Multithread | Single Diff | Multi Diff |
| E5-2690 V3 | 24:48 | 63.2°C | 401 | 385.78 | 1915 | 16007 | -1.0% | -15.1% |
| E5-2695 V3 | 28:56 | 55.1°C | 352 | 388.96 | 1790 | 16528 | -7.5% | -12.3% |
| E5-2698 V3 | 32:64 | 53.1°C | 415 | 436.25 | 1935 | 18842 | 0.0% | 0.0% |
|
||||||||
The 16-core CPU at 2.3 GHz does better at single thread operations than the 12-core does at 2.6 GHz. That is what makes the 16-core CPU my choice. Each core executes more code per unit time than those in the 12- and 14-core CPUs. The 14- and 16-core CPUs have a 2.3 GHz clock, while the 12-core runs at 2.6 GHz. The actual average CPU speed during the tests was 2.7 GHz for the 12-core and 2.5 GHz for the 14- and 16-core CPUs.
Case
The case is great, but the EEB-size motherboard covers all the cable routing holes on the back. I had to install the cables before the motherboard, and doing that with the stiff extensions proved to be a challenge. That was also my first time dressing up the cables. It shows in the final result. When I do the workstation I'll try to do better, but there won't be the huge motherboard to contend with. EDIT: The workstation has a motherboard with a steel plate on the bottom. There was only 1 mm or so space under the MB. And being an "E-ATX", it covered the holes in the back panel. I had to route all cables through slots at the top and the bottom.
Side note. If you get this case, and if you lose the top filter, before tearing the room apart looking for it, save a couple of hours and look on the metal side of the case. The filter is magnetic. The filter on the top is controversial. It filters the air leaving the case. There is no filter on the front, where the air comes in. I put some on the fans and then a filter inside the entire front. It cuts the airflow a bit, but the airflow in this case is so unbelievably strong that losing a significant percentage makes it only 50% better than most cases. The reduced airflow is more than made up for by the lack of problem-causing dust on the VRMs and other critical parts. When I tore my workstation apart, there was dust caked on the radiator, blocking much of the airflow. I hope the filters stop that.
If you use those cheap nylon screens in a PVC frame, buy twice as many as you need, and sort them into two equal stacks - the tighter ones and the looser and floppier ones. Then, using an X-Acto knife, cut the screen out of the loose ones and use the frames as a spacer for the tight ones. Without the spacer, the filter net hits the center hub of the fan causing a louder whining noise and could damage the fan if it shredded.
Cost
| Item | Cost | Description |
|---|---|---|
| Motherboard | $125 | Huananzhi X99 F8D Plus dual Xeon motherboard. ($237@Newegg $129@AliExpress) |
| 64 GB Memory | $212 | CMS DDR4-19200 2400 MHz 32 GB for each CPU (4x 8 GB) CL17, X8, 1.2V, Unbuffered, DIMM total 64 GB. Newegg |
| 2x CPU coolers | $120 | Noctua NH-D9DX i4 3U the only one that would fit with the CPUs being so close. ($260@Newegg or $120@Amazon) |
| 2x E5-2698 V3 | $13 | 16-core 32-thread Xeon ebay |
| Case | $65 | Montech AIR 903 Base White Newegg or Amazon (Amazon delivery takes 6 days longer. They get it from Newegg) |
| PSU | $80 | Cooler Master MWE Gold 850 V2 Fully Modular. Newegg. I'm not saying this is the only PSU, but it's 850 W and inexpensive.. |
| 2x 140 mm Fans | $35 | Corsair non-ARGB white fans for the top of the case. Newegg or Amazon |
| 2x 120 mm Fans | $30 | Corsair non-ARGB white fans for the bottom of the case. Newegg or Amazon |
| Fan Hub | $11 | EZDIY-FAB 10-port splitter. There are 9-fans - 7-case fans, 2-CPU fans. Amazon |
| Total | $691 |
That's if you have to buy everything. I bought everything. The power supply only because I was missing the SATA power cables. The SATA power drives the fan hub. I was lucky to start buying pieces during November at Newegg. Everything was marked down. For instance the RAM I paid $212 for went up to $560 after the sales were over, and the price of the motherboard went up to $337, then down to $219 a few days later, then back up to $337. It was shipped from the USA; Now it's shipped from China.
You may notice I did not include a video card of any kind. I had an ASRock RX-6600 in the old server. I don't think of servers as having fancy video cards, but I had it. You might want a $30 video card or a $3000 video card – I don't know. Pick what you think you'll need. It takes very little for a server. I run the same OS on the server as on the workstation, so a similar card made some sense for me. Keep in mind the motherboard supports PCI-E 3.0. No sense in getting a video card that supports PCI-E 5.0. It will work, but it's a waste of money.
Also salvaged from the old server were 2x 1 TB NVMe SSDs.
With some of the money I saved on the dinosaur technology I was able to buy a new case for my workstation (same case) and power supply cable extensions for both. Watch out for price gouging on those. You can get 16 ga dual CPU sets from Amazon for $30. I didn't find any for 2 CPUs at Newegg. Odd, since my 2022 Z690 Aorus Master, bought from Newegg, has 2 CPU power connectors as does my old Corsair PSU.
Performance is very noticeably improved since the upgrade from single to dual E5-2690 V3s and better yet when I changed to the E5-2698 V3s. As seen above, the dual E5-2698 V3 outperforms the i9-12900K in the Blender test 436 to 414, but it is a power hog. Idle power consumption on the server is around 100 watts, while on the workstation it is around 85 watts. I attribute that to the fact that the idle clock on the i9 is 800 MHz while the idle clock on the Xeon is 1.2 GHz.
If you made it this far, you are probably interested in building a dual CPU server. I did not scrimp on parts. The motherboard was a gamble, but it turned out ok. You can find fans and coolers cheaper than my prices, at least in November, and you are likely to have some parts lying about. The Minecraft servers are fast, and the network speed is astronomical. Running Git is instantaneous. I'm really happy with the way this project turned out.
Appendix A
The BIOS has a 2 digit display that shows codes for each step in the initialization phase. The codes are generally errors if the display stops on them, otherwise they show the phase the BIOS is in:
| Problem | Codes |
|---|---|
| CPU Error | 00, C0, CF, D0, F1, FF |
| DRAM Error | 01, 62, 64, 69, 6F, A7, B0, B4, B7, B9, BA, C1, C6, D3, D4, D8, E1 |
| Graphics Card Error | 0A, 0B, 0D, 24, 25, 26, 2A, 2B, 31, A6, AE, B2, D6 |
| BIOS Check Error | C1, C6, 01, 02, 19 |
| POST Finished Without Error | 40, 4E, 55, 73, AA |
| Hard disk or Graphics card error | A6, AB, AE |
| OS Not Installed | AE |
| DRAM Clock is Too High | BF |
| Incompatible DRAM | B1 |
| DRAM Error | 67 |
| DRAM Not Installed | 53 |
| CPU Error | 91 |
I don't know where these codes came from; I saw a screenshot of a webpage. I saw about half of these codes on the first motherboard I got. The working board goes through dozens of codes before landing on "AA". Then the OS boots. Codes A6 & AE are duplicated because different errors can result in the same code. For example, AE could be the boot record on the disk, an empty disk, or other reasons.