Ever wondered if you could cram serious gaming power into a tiny, one-liter office Rugged Mini PC? Well, this project takes a $100 Lenovo ThinkCentre M920q and transforms it into what might just be the most upgradeable mini PC out there. We’re talking about upgrading everything from the CPU and RAM to adding a full-size graphics card, all while keeping the footprint incredibly small.
The Starting Point: A Humble Office PC
This Lenovo M920q, picked up for a mere $100, is a compact machine with a lot of potential. It comes with a basic 65-watt power supply, which is definitely not enough for the upgrades we have planned. Getting inside is super simple – just one screw at the back, and the lid comes right off. What’s cool is how much flexibility it offers for upgrades. There’s even a bracket for a 2.5-inch SATA SSD, which is pretty neat for a small form factor Rugged Mini PC.
Inside, we find the slot where a graphics card will eventually go. It also has a small subwoofer, which is a nice touch. Accessing the RAM and storage is just as easy; another panel on the bottom opens up. My unit came with a single 8GB stick of RAM and a small 256GB SSD. There’s even space to solder another SSD, though that’s more for a different version of this PC. The stock cooling system is pretty basic, an aluminum heatsink weighing only 77 grams. But the real star is the CPU socket, which supports Intel 8th and 9th gen desktop processors – not some weak mobile chips, but actual powerful CPUs.
Right now, with its stock Pentium processor (a dual-core, four-thread chip that sips a mere 22 watts), it’s not exactly a gaming powerhouse. Even this weak CPU gets pretty hot, hitting 85°C on the VRM. Games like GTA V on minimum settings will run, but don’t expect smooth gameplay. Adding a second stick of RAM actually boosts FPS by a noticeable 50%, so dual-channel memory is a must, especially with the integrated graphics.
Upgrading the Core: CPU and Cooling
Time to give this little machine some serious upgrades. First up, the CPU. We’ll remove the stock cooling, give the heatsink a clean (every degree counts!), and reapply thermal paste. The old paste was practically dry, which explains the high temperatures.
For the CPU upgrade, we have a couple of options: an i7-9700 with eight cores or an i5-8500. We’ll start with the i7-9700. We’ll also be using Thermal Grizzly liquid metal for better heat transfer. For the power supply, we need something beefier than the stock 65W unit. Luckily, a subscriber sent over a much more powerful 85W unit.
With the i7-9700 installed, the CPU hits 100°C, and the VRM overheats at 95°C. Even undervolting doesn’t fully solve the VRM overheating issue because the CPU is just too powerful for the board’s power delivery.
So, we switch to the i5-8500 and undervolt it to 40W. This gives us a good balance of performance and manageable temperatures. The VRM still gets hot, reaching 93°C during a stress test, but it should be less in actual gaming. To help with VRM temps, we’ll add small copper heatsinks to the VRM components. While not a perfect solution, it should slow down the heat buildup.
Pushing the Limits: Delidding and Liquid Metal
Next, we’re going to delid the CPU. This involves carefully slicing through the sealant on the CPU lid with a razor blade to expose the actual processor die. It’s a risky process, and you need to be careful not to damage any small components. In this case, the inside had thermal paste, not solder, which is common for non-K series CPUs.
After cleaning off the old sealant and thermal paste, we apply liquid metal to the CPU die and the CPU lid. We also tin the lid to ensure good contact. Then, we use a bit of high-temperature silicone sealant to reattach the lid. After letting it set, we reinstall the CPU with fresh thermal paste (liquid metal can’t be applied directly to the aluminum heatsink). The result? A 4°C drop in average temperature and a 9°C drop at the maximum. The VRM still overheats slightly, so we had to slightly lower the CPU’s clock speed, but it’s a definite improvement.
Adding Graphics Power: The RTX 4060
Now for the most exciting part: adding a graphics card. We’ll install 32GB of RAM, which is a significant upgrade. A subscriber also sent over an adapter for the RTX 4060. Even though the card has an 8-pin power connector, the motherboard’s PCIe slot can only provide 50W. The extra power connector on the GPU is key here.
To fit the full-size RTX 4060, we need to remove some parts of the case, like the display port bracket and a front reinforcement bar. The GPU will stick out a bit, so it’s no longer a strict one-liter build; it’s closer to 2.5 liters now. We’ll also need a Flex ATX 500W power supply to handle the GPU.
To power on the Flex ATX PSU, we need to short two pins on its main connector. Once everything is connected, we power on the PSU first, then the PC. It works! The i5 runs at 3.7 GHz, and games are hitting 70-80 FPS.
We did encounter an issue where the CPU frequency would drop drastically. Initially, we thought it was VRM overheating, but it turned out to be related to the GPU’s power draw from the PCIe slot. By limiting the GPU’s power and undervolting it, the problem was resolved.
We also tested the i7-9700 again, running it at 3.4 GHz on all cores to avoid VRM issues. This configuration was about 15-20% faster than the i5. For comparison, a more robust motherboard with better VRM cooling could handle the i7 at full speed, reaching 4.4 GHz and providing a much smoother gaming experience.
The Final Build and Cost
So, what’s the total cost for this beast?
- Rugged Mini PC (Lenovo M920q): $100
- CPU (i5-8500): $35
- RAM (32GB DDR4): $50
- Riser Cable: $10
- Mini PC Power Supply: $20
- GPU Power Supply (Flex ATX): $50 (estimated)
- Graphics Card (RTX 4060): $280
Total Build Cost: $545
The final volume is around 2.5 to 2.75 liters. It’s not a one-liter PC anymore, but it’s still incredibly compact for the performance it offers. It’s a fun project that shows just how much you can push the limits of small form factor PCs.
Key Takeaways
- CPU Upgradeability: The Lenovo M920q supports powerful desktop CPUs (8th/9th gen Intel), offering a significant performance boost over stock.
- Cooling is Key: Even with powerful CPUs, VRM and CPU temperatures can be an issue. Liquid metal, heatsinks, and undervolting are important for managing heat.
- GPU Integration: Fitting a full-size GPU requires case modifications and a more powerful external power supply (like a Flex ATX PSU).
- Power Delivery Limits: The motherboard’s VRM and PCIe slot power delivery can be a bottleneck, sometimes requiring undervolting or lower clock speeds.
- Cost vs. Performance: For around $545, you can build a very capable mini gaming PC that punches well above its weight class in terms of size.
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