Brains Box · purchase decision · v2 (revised)

Buy Decision: the headless fleet box

Revised after a multi-model cross-examination. The headline changed: the right buy is a refurbished business Small Form Factor (SFF), not a Micro/Tiny. The reason is expandability — four DIMM slots and real storage paths — which a 1-liter Micro cannot give you.

Revised June 20, 2026 · workload: always-on Node daemon + ~10 CLI workers + growing vector DB, inference via cloud APIs (no local GPU needed)

The recommendation

Refurbished 10th-gen business SFF · 6c/12t · 32GB as 2×16GB with two DIMM slots still empty · 1TB TLC NVMe · open M.2 or SATA path. Dell OptiPlex 5080/7080/7090 SFF, HP EliteDesk 800/805 G6 SFF, or equivalent Lenovo SFF. 8 cores are welcome headroom but not mandatory; buy them only at a small premium. ECC unnecessary. Add a small UPS. Start at 1TB if there's a free drive slot, 2TB if it's the only drive bay.

Target: ~$350–450 delivered for a 10th-gen 6-core SFF with 32GB/1TB.

What changed from my v1 page (owning the errors)

Form factor flip: v1 led with Micro/Tiny. An SFF is the better call — 4 DIMM slots let you run 2×16GB now and leave two open for a clean 64GB upgrade. A 2-DIMM Micro fills both with 32GB and leaves no room.
Lenovo M70q Gen3 was wrong: v1 called it 8c/16t with dual M.2 storage. It's actually a 6c/12t-class (i5-12xxxT) 12th-gen with one M.2 SSD + a 2.5" SATA — the "second M.2" is for WiFi. I confused it with the higher-tier M90q Gen2/3 (which does have dual NVMe). Removed from top spot.
Prices were stale: the ~$370–400 7080 eBay figure wasn't reliably reproducible on re-check; the Beelink SER8 sits far above the quoted range. Treat all prices as leads, verify the live SKU.
"Open RAM slot" requirement: v1 ignored it. It's now a hard filter — reject anything that fills every DIMM slot at 32GB.
Don't overpay for cores you won't bottleneck on, or for a Radeon/iGPU and NPU the server never uses.

The four tiers

Tier A · best overall

10th-gen business SFF

$350–450

32GB/1TB · ~$500–650 for a known-TLC 2TB

Dell OptiPlex 5080/7080/5090/7090 SFF · HP EliteDesk 800/805 G6 SFF · HP ProDesk 600 G6 SFF · Lenovo M80s/M90s. Preferred CPU: i5-10500/10505 or Ryzen 5 PRO 4650G (i7-10700 only at a small premium).

+ 4 DIMM slots (2 open for 64GB), real M.2 + SATA + PCIe expansion, serviceable, cheap parts.
− Bigger footprint than a Micro.

Search SFF listings →

Tier B · best compact

High-tier business mini

$375–625

10th-gen ~$375–475 · 12th-gen ~$475–625

Dell OptiPlex 7080 Micro · Lenovo M90q Gen2/3 · HP Elite Mini 800 G9. Verified dual-storage minis only. The 7080 Micro hardware is sound (genuine i7-10700T 8c/16t, two storage M.2 + possible SATA).

+ Tiny footprint, low idle power.
− Usually only 2 SO-DIMM slots (32GB fills both unless you buy 1×32GB single-channel). External power brick.

The 7080 Micro eBay listing →

Tier C · new consumer mini

Dual-M.2 mini (new)

$450–550

32GB/1TB · verify all-in, not barebone

GMKtec M6/M7 Ultra · Minisforum UM760-class · Beelink SER8 (only on a deep sale). Strong CPUs (Ryzen 8c/16t), dual M.2, 2.5GbE.

+ Brand new, no refurb gamble, current silicon.
− Pay for a strong iGPU you won't use, 2 SO-DIMMs, less predictable parts/firmware/warranty. SER8 only worth it ≤~$500–550 at 32GB/1TB.

Search new minis →

Tier D · budget

Older 8th/9th-gen SFF

$275–325

up to ~$350 only with strong warranty / 2TB

HP EliteDesk 800 G4/G5 SFF · Dell OptiPlex 7060/7070 SFF · Lenovo M920s.

+ Cheapest path to a 4-DIMM expandable chassis.
− Older single-thread speed; near $350–400 it competes too closely with a 10th-gen 6-core. Buy only if genuinely cheap.

Search budget SFF →

Live listings — best 5, scored (June 20, 2026)

Top live pick

Dell OptiPlex 7080 SFF · i7-10700 (8c/16t) · 32GB · 1TB NVMe · $359 delivered Sage Sustainable Electronics (Microsoft Authorized Refurbisher), 1-yr warranty + 30-day returns. Hits everything: SFF expandability (4 DIMM, dual storage M.2, SATA bays), the 8-core headroom our Chromium/OCR load actually uses, and the lowest confirmed price — under the $450 ceiling. This is the buy.

→ View the $359 Sage SE listing

#	Model (SFF)	CPU	RAM	Storage	Seller / warranty	Delivered	Score	Verdict
1	Dell OptiPlex 7080 SFF Sage SE listing →	i7-10700 8c/16t	32GB / 4 DIMM (~2 free)	1TB NVMe · 2nd M.2 free + 3 SATA	Sage SE (MS Auth Refurb) · 1yr + 30-day	$359	88	BUY
2	Dell OptiPlex 5080 SFF eBay listing →	i5-10500 6c/12t	32GB / 4 DIMM (2 free if 2×16)	1TB NVMe · 1 M.2 used + 3 SATA	eBay Refurbished (Allstate 1yr) · 30-day	~$385–420	82	BUY
3	HP EliteDesk 800 G6 SFF Newegg →	i5-10500 6c/12t	32GB / 4 DIMM (2 free if 2×16)	1TB NVMe · 2nd M.2 free + SATA	HP refurb · Newegg · 1yr	$464.99	79	BUY
4	Lenovo ThinkCentre M80s SFF Amazon →	i7-10700 8c/16t	32GB / 4 DIMM (confirm 2×16)	1TB SSD (confirm NVMe!) · 1 M.2 + SATA	Amazon Renewed · 90-day+ · 30-day	~$449–499	75	NEGOTIATE
5	HP EliteDesk 800 G6 SFF (i7) Best Buy →	i7-10700 8c/16t	32GB / 4 DIMM (2 free if 2×16)	512GB NVMe · 2nd M.2 free	HP refurb · Best Buy · 1yr	~$479–529	72	NEGOTIATE

Verify before buying: confirm RAM is 2×16GB (not 4×8GB or 1×32GB single-channel), the SSD is a known TLC brand (Samsung/WD/SK Hynix, not QLC OEM filler), the 2nd M.2 is storage-capable (not the WLAN slot), OEM power adapter included, and BIOS admin password cleared. Only the $359 Sage SE price was fetched live and confirmed; ranks 2/4/5 are ±$20 market estimates (eBay/Amazon/Best Buy block automated fetch) — inventory turns over in days, check the same day you buy.

Buying order (what to reach for, in sequence)

Best exact fit: 10th-gen SFF, 6c/12t, 32GB as 2×16GB, 1TB known TLC NVMe, two DIMMs free, empty M.2 or SATA path.
Best smaller option: Dell 7080 Micro or Lenovo M90q with verified dual NVMe — configured 1×32GB only if the open-slot rule is strict.
Best newer option: a 12th-gen business i5 when the total premium over Tier A is under ~$150.
Best new consumer option: a Ryzen dual-M.2 mini only when its complete 32GB/1TB price is at/below the business alternatives with acceptable warranty.
Don't overpay for an i7, Radeon 780M, NPU, Wi-Fi 7, or 10GbE the workload will never touch.

What actually matters

RAM topology is the real spec

For an HNSW vector DB, RAM is the likely first bottleneck. Want: 32GB as 2×16GB (dual-channel now) with two empty DIMM slots for a no-waste 64GB later. That's the whole case for SFF over Micro.

6c/12t is the sweet spot

Workers mostly wait on cloud APIs and I/O. 6 modern cores is the price/performance pick. Pay for 8c/16t only at a ~$50–75 premium — OR because we run persistent Chromium/Playwright fleets + OCR + ingestion, which is exactly when 8 cores earn their keep.

Storage: 1TB + a path, or 2TB if one bay

1TB TLC NVMe with a free second slot + off-box backups is fine (~18–20GB/mo growth budget over 3 yrs). Choose 2TB up front only if it's the single drive bay or you keep local raw assets/snapshots. Don't RAID-0 to fake capacity.

Skip ECC, skip the iGPU tax

ECC isn't cost-effective here — prioritize UPS, off-box backups, tested restores, SSD health monitoring. And don't pay for a strong integrated GPU; this box never renders.

Verify the exact SKU before buying

The "i7" badge is meaningless (8700T=6c, 9700T=8c/8t, 10700T=8c/16t). Confirm exact CPU SKU, RAM layout (1×32 vs 2×16), storage M.2 slots not counting WLAN, SSD model/wear, BIOS unlocked, warranty + 30-day returns.

Headless setup

Line-interactive UPS, BIOS "restore after AC loss" on, sleep disabled, wired Gigabit, SSH keys + Tailscale before you tuck it away. Test a no-monitor boot and a post-reboot remote login.

If you specifically want the 7080 Micro

The hardware is genuinely good (real 8c/16t i7-10700T, two storage M.2 positions). Two cautions: the headline ~$370–400 price wasn't reproducible on re-check, and a 32GB unit often ships as 2×16GB (no open slot) — to keep a slot free you'd run 1×32GB single-channel. Buy rule: attractive at ~$400–475 with 32GB/1TB, dual-NVMe hardware present, good warranty.

→ The original eBay 7080 Micro listing (verify the live SKU, RAM layout, and price before buying).