August 20, 2026, twelve days before the fall term. The lab administrator at a secondary school in Huizhou walked into the third computer room, pressed the power button, and watched the fans in the front row spin while the screens stayed black. With the side panel off, the cause was visible: a coin-cell battery on the restore card had leaked and corroded the slot around it.
Three machines were already down before term for the same reason. The principal's question was blunt: could the school keep its monitors, replace only the PCs, hold the budget to 200,000 RMB, and have the lab ready before students returned? No class could be lost, and the calendar was tight.
The site in three numbers
The lab had 56 PCs bought in 2016, each with a Core i3-6100, 4 GB of RAM, a 500 GB hard drive, Windows 10, classroom-management software, and a hardware restore card. The purchase order looked reasonable. The operating numbers did not:
| Measure | Before | Note |
|---|---|---|
| Fleet | 56 PCs | Bought in 2016; i3-6100, 4 GB RAM, 500 GB hard drive |
| Boot to desktop | 170 seconds | Slower once classroom software and antivirus loaded |
| 50 simultaneous logins | About 480 seconds | Machines were powered on ten minutes before class, which often cut it close |
The restore card was the bigger problem. Its model had been discontinued, its battery was aging, and it failed three or four times a semester, typically by letting student changes survive a reboot. Each incident meant rebuilding a whole room: two days of work for one administrator.
Diagnosis: memory and disk, not the CPU
The first instinct is to blame the processor. That instinct was wrong. The i3-6100 is a dual-core, four-thread part, and it handles office work and classroom broadcast well enough. The bottlenecks were elsewhere:
- 4 GB of memory. Windows 10 takes about 2.8 GB at boot. Add classroom software, a browser, and Office, and the machine runs out of memory and starts paging to the hard drive.
- A 500 GB hard drive. 4K random reads ran at roughly 0.5 MB/s. A boot cycle touches thousands of small files, so 170 seconds was normal, not an anomaly.
- The restore card. Write protection sends every change back to disk on reboot, which is hard on a mechanical drive. Once the battery failed, protection came and went.
A memory and SSD upgrade would have relieved the symptoms, but the 2016 platform had two or three years left at most, and DDR4 prices were still climbing. Spending 67,000 RMB to extend it made little sense.
Three options against a 200,000 RMB ceiling
We priced three paths against that ceiling.
| Option | Approach | Budget | Verdict |
|---|---|---|---|
| A. Virtual desktops | 56 thin clients plus servers | 280,000 RMB and up | Over budget, outage risk, no dedicated virtualization administrator |
| B. New commercial PCs | 56 units with i5, 16 GB, 512 GB NVMe; old monitors kept | 205,000 RMB | Fits, with three-year on-site service |
| C. Memory and SSD upgrade | Add 8 GB and a 512 GB SSD to each old PC | 67,000 RMB | Platform too old; replaced again in two years |
Option B won, on one condition: split the order. Forty units were installed during summer break, the remaining sixteen in the first week of term, and eight of the better old machines stayed as spares and exam machines. That kept the opening week intact.
Configuration
The specification was deliberately modest. A general school lab does not need discrete graphics.
| Item | Specification | Quantity |
|---|---|---|
| Desktop | i5-12400 (6C/12T), 16 GB DDR4, 512 GB NVMe, integrated graphics, three-year on-site | 56 |
| Monitor | 23.8-inch IPS, 1920 x 1080, HDMI and VGA | 48 (8 old monitors kept) |
| Classroom software | Existing package reused; teacher console reinstalled | 1 set |
| Restore | Software restore on UEFI in shadow mode; no hardware card | 56 seats |
| Network | Existing gigabit switches unchanged; 12 Cat6 patch cables added, labels redone | n/a |
Eight old monitors stayed on the spare and exam machines, so the order included 48 new screens for the teaching desks. The existing classroom software was reused rather than replaced; only the teacher console needed a clean install.
Rollout: two days per batch, no lost class time
- August 21-22: Batch 1, 40 units. Old machines out, new ones in, operating system and classroom software installed, then broadcast and restore tested seat by seat.
- August 23: Stress test on the 40 new machines.
- September 3: after batch 2, a full 50-machine test: boot, log in and submit homework together.
- September 2-3: Batch 2, 16 units, installed during lunch breaks and after dismissal.
- Old equipment: Eight of the best machines kept as spares; the rest had their drives removed and went through the school's asset process.
No machine was swapped during a lesson. The second batch waited for lunch breaks and the end of the school day, which is how the school avoided disrupting classes mid-term.
Results
Boot time fell from 170 seconds to 18 seconds. Fifty simultaneous logins, which used to take about eight minutes, finished in 85 seconds. In the first week of term, the lab no longer produced the familiar scene of a class starting with half the room still loading.
The administrator's favorite change was the software restore. A student can wreck the system settings and a reboot restores them; nobody opens a case to pull a card anymore.
The bill: where 205,360 RMB went
The order came to 205,360 RMB, a little over the 200,000 RMB the principal had named.
| Item | Amount |
|---|---|
| 56 commercial desktops at 2,850 RMB | 159,600 RMB |
| 48 monitors at 620 RMB | 29,760 RMB |
| System, classroom software, and restore deployment | 9,000 RMB |
| Cabling, labels, and old-machine inventory | 7,000 RMB |
| Total | 205,360 RMB |
Two choices kept the price down: eight old screens stayed in service, and the desktops shipped with integrated graphics rather than a discrete card. The desktops themselves were 159,600 RMB of the total, and the deployment line covered the operating system, classroom software, and restore setup — the work that makes 56 machines behave identically.
Five lessons
- Skip the discrete GPU in a general lab. Classroom broadcast, office work, and programming classes do not use one. It only adds failure points and power draw.
- 16 GB is the floor. With 8 GB, a current operating system plus classroom software will feel slow again within two years.
- Retire the restore card. Software restore can be managed remotely and updated in bulk; the cost is dependence on the operating system itself. For a secondary school lab, the trade is worth it.
- Keep at least 10% spares. Eight spares for 56 seats meant exam season did not have to wait on a repair ticket.
- Buy in batches. Replacing everything at once looks tidy, but budget, installation, and acceptance all collide. Two batches are steadier.
Note: At the client's request, the school's name, the names of its internal departments, and some dates have been generalized. Specifications and prices reflect the October 2026 market; an actual project depends on a site survey.