Challenge of Two Cases

Small and portable PCs are an attractive computing option. Unfortunately, they are at odds with much of the technical networking world. If you merely need one large graphics card or one beefy 10GbE networking card, you can get away with your MiniITX form factor system.

Contrast that with doing WiFi and wired network testing: often you want a system that can emulate an upstream network and emulate user clients on WiFi. This means two 1GbE ports to bond with a 4×4 Access Point these days. You can maybe get by with a mini ITX if it somehow had multiple 1GbE ports (like an AsRock Rack motherboard would), but that’s not the common request I’m hearing.

Let’s go for two 4×4 nics, 1 3×3 nic, and one 2x 10GbE card. Four slots. First challenge: a reliable MicroATX motherboard: a SuperMicro x11ssm-f will work pretty well. Second challenge: a case. Well, people often don’t consider a 2U rack mount case “portable.” The dimensions on that are often 17x14x3.5in. Most home theater PC cases are actually quite close to that size, or larger. Most of SilverStones HTPC cases are 18x15x4.5.

Antec has an attractive case: VSK2000-u3: 14 x 13 x 4in. This case can sit horizontal or vertical. It appears to be the smallest MicroATX case on the market. It comes with a 92mm case fan that is PWM* (once you strip and re-wire the plug). It requires a TFX power supply which limits us to 350W. This is sufficient, but we lack air draw thru such a small PSU.

Rosewill has a very small MicroATX case that might be more useful: 15.74 x 14.4 x 7.3in. This case is bigger. It’s a mini-tower and has a vertical tower orientation. Anything bigger might be harder to ship, but doesn’t have much bearing on the weight. We can fit an ATX power supply in this case, allowing us up to 750W with ease, and plenty of air draw through all parts of the case.

A desktop environment is the typical setting for a portable case unit. Fans are a challenge, and the premium silent fans (think Noctua) just don’t produce adequate airflow for such high heat density. We’re combining an 80W processor plus ~50W of network cards right next to each other with only about 30-50 CFM airflow through the whole case. Coolers that fit a HTPC form factor case come with 92mm x 15mm fans which move about 28-35CFM, and tend barely to keep the system below 73C. That is not adequate. A 2U server does a much better job at cooling at the cost of noise, however, with 3000RPM fans.

So which case is better? The smaller case that you have to discard your stock fans out of (discard the vertical heat sink fan for a 92x25mm ~50CFM fan, along with case fan)? Extra effort, waste. Or the bigger system that will allow a 120mm fan on a tower cooler?