The typical rule of thumb is that building your own computer from components is far cheaper than buying a prebuilt machine. Buying parts from Newegg.com, Amazon, Fry's Electronics, etc. results in a better machine for less money than getting something from Dell. This was certainly true when I embarked on the Luggable PC project but a few notable events have since occurred to make an exception to the rule.

The blockchain fad is the biggest disruption. Cryptocurrency miners' demand for graphics processors drove up their prices tremendously. At the beginning of my Luggable PC project, a NVIDIA 1060 card with 6 GB memory is considered a good mid-range GPU. (Or an entry-level unit for the more demanding world of virtual reality). A desktop 1060 video card was available for around $200 and I expected its price to drop as I designed and built my luggable PC. Instead, it spiked up to over $400 at times and is now hovering around $300.

The second disruption is in 3D-NAND flash memory. It is a big step change in price/performance so flash memory makers had no choice but to switch to 3D NAND technology or risk going out of business long-term. In the short-term, chip fabrication facilities have to be taken offline for this conversion, which meant a shortage of flash memory, 3D and otherwise, across the market. Driving up prices of solid state drives.

The third disruption is in DDR4 memory. There isn't as clearly a single factor here but manufacturing capacity seems to be lagging market demand over the past year or so. Right now, DDR4 memory is nearly double the price of similar capacity DDR3 memory when historically they should be closer to price parity at this stage of technology maturity.

There are a few other factors at play, but the short-term trend is clear: many computer components have risen in price over the past year, counter to the long-term historical trend of ever-cheaper electronics.

Computer manufacturers like Dell deal in large quantities, and therefore they buy through supply contracts whose prices are independent of day-to-day market disruption. The upside of this approach is that, in times of supply shortages, Dell pays far less for their parts than market price.

Today's example: a particular configuration of Dell Inspiron 15 7000 Gaming laptop is available for $750 after promotional discount codes. Let's look at the components and the current (approximate) market price for their desktop counterparts.

• NVIDIA GTX 1060 with 6GB: Admittedly the laptop variant of this GPU is slightly less capable than its desktop equivalent, but for the purposes of this comparison we'll count it at the full $300.
• Intel Core i5-7300HQ: Again this is a laptop-only part. It is similar to the desktop i5-7400 processor in that they both have a peak speed of 3.5 GHz, so $200.
• 256GB NVMe M.2 SSD: Unlike the other parts, desktop machines are happy to use the exact same M.2 form factor solid state drives using the NVMe interface. 256 is a little cramped but on a laptop it should be fine. (I stuck with 256 until the flash memory crunch eased a bit for me to upgrade to 512.) Let's call it $100.
• 8GB DDR4 memory at 2400MHz: The smaller laptop-sized DDR4 modules are a little more expensive than their desktop counterparts, but we'll round up to $100.

With these rough estimates, we're already up to $700 and we're still missing some major components necessary for a working computer.

• Motherboard with M.2 SSD slot and built-in WiFi: Bottom of the line units are available for $70-80 but a reputable unit will be $100 and up. (It is the backbone of the system so not the best place to economize.)
• Power supply: We can pinch a bit here, reliable though not super powerful units can be had for around $50.
• Display: A 1920x1080 IPS monitor will be around $100.
• Keyboard, Mouse, case (luggable or otherwise) and other miscellaneous parts: Round to $50 for a nice even tally.

That's $1000 to build a desktop or luggable PC with similar specs as this $750 Dell laptop. And while the screen might be physically larger, the whole computer definitely won't be as lightweight and portable. Such laptop-only traits - light weight, tight integration, ability to run on battery - usually demand a price premium over equivalent desktops.

But things are weird in a distorted market.

(Cross-posted to NewScrewdriver.com)