Less than most buyers expect, at least on the current generation. The ASUS NUC 15 Pro comes in a Slim chassis 36.8 mm high and a Tall chassis 54 mm high, with the same 117 x 112 mm footprint, the same processors and, according to ASUS's spec page, the same ports. The big difference on older NUCs was the Tall model's 2.5-inch drive bay, and that is gone: ASUS lists no 2.5-inch bay on either NUC 15 Pro chassis. What the extra height buys now is room for optional add-ons, which reviewers say include a second M.2 2280 slot or a second network port. At SourceIT the Tall is actually the cheaper box: the NUC 15 Pro Tall Core Ultra 5 225H barebone is S$642.07 against S$686.22 for the NUC 15 Pro Slim with the same processor (listed 3 Nov 2026).
What actually differs between Slim and Tall?
| NUC 15 Pro Slim | NUC 15 Pro Tall | |
|---|---|---|
| Size | 117 x 112 x 36.8 mm | 117 x 112 x 54 mm |
| Weight | 0.51 kg | 0.58 kg |
| Processors | Same range: Core Ultra 7 255H / 265H, Ultra 5 225H / 235H (40W), Core 7 240H, Core 5 210H, Core 3 100U (25W) | |
| Memory | Two SO-DIMM (DDR5-5600) or CSO-DIMM (DDR5-6400) slots | |
| Built-in storage slots | M.2 2280 (PCIe 5.0 x4 on Core Ultra) plus M.2 2242 (PCIe 4.0 x4) | |
| 2.5-inch drive bay | No | No (the NUC 14 Pro Tall had one) |
| Ports | 2x Thunderbolt 4, 2x HDMI 2.1, one 2.5GbE port, front 20Gbps USB-C, USB-A | |
| Extra room for | Nothing extra | Optional expansion: a second M.2 2280 slot, a second 2.5GbE port or LAN + RS232, as reported by reviewers |
| SourceIT barebone, Core Ultra 5 225H | S$686.22 | S$642.07 |
| SourceIT barebone, Core Ultra 7 255H | S$821.72 | S$749.25 |
Dimensions, processors, memory, storage and ports from ASUS's NUC 15 Pro and NUC 14 Pro spec pages (accessed 3 Nov 2026). Expansion options from Club386 (Feb 2025) and Starry Hope (Oct 2026); ASUS's spec page does not list them, so check availability before you rely on one. SourceIT prices listed 3 Nov 2026. We have not tested these units ourselves.
Why did the 2.5-inch bay matter, and where did it go?
On the NUC 14 Pro, the Tall chassis was the one to buy if you wanted a cheap, large SATA SSD or a hard drive alongside the M.2 boot drive. ASUS's NUC 14 Pro spec page marks the 2.5-inch bay as "Tall Chassis Only". The NUC 15 Pro spec page lists no 2.5-inch bay at all, for either height. So if you are replacing a NUC 14 Pro Tall that holds a 2.5-inch data drive, plan to move that data to the second M.2 slot, an external drive or a NAS.
On the NUC 15 Pro, choose the Tall for what you might add later, not for what is inside on day one.
When is the Tall worth choosing?
- You may need a second wired network port. The NUC 15 Pro has one 2.5GbE port. Reviewers report a second-LAN option for the Tall, which matters for firewall labs, network monitoring or a PC on two separate networks. Confirm the option is available in Singapore before ordering.
- You want a third M.2 drive. The reported extra M.2 2280 slot gives room for a large second SSD while keeping the PCIe 5.0 slot for the system drive.
- You need a serial port. The LAN + RS232 option suits retail, kiosk and industrial equipment that still talks over RS232.
- You want a ready-made system. At SourceIT the NUC 15 Pro full systems with RAM, SSD and Windows 11 Pro are Tall units, such as the NUC 15 Pro Tall Core Ultra 5 225H, 16GB (2x8GB), 512GB, Windows 11 Pro at S$1,363.06.
When is the Slim the better fit?
- Behind a monitor or display. Both chassis ship with a VESA bracket, but 17 mm less depth off the back of a monitor or a signage screen is easier to hide.
- Under a counter or in a drawer. Reception desks, POS counters and meeting-room credenzas often have tight vertical space.
- You will never open it. If the PC will run one job with the storage it has, the extra height does nothing for you.
We found no published test comparing Slim and Tall temperatures or noise with the same processor, so we do not claim the Tall runs cooler. One review of the NUC 15 Pro Tall with a Core Ultra 7 255H measured about 45 dB under heavy load and found it barely noticeable in office work. For how small form factors trade off against heat and expansion, see The Hidden Problem With Mini PCs: When Small Becomes Too Small.
What about the NUC 16 Pro and NUC 15 Pro+?
There is no Slim or Tall choice. Both use a single 144 x 112–117 x 42 mm chassis. The NUC 16 Pro gets two 2.5GbE ports as standard, which removes one of the main reasons to pick a Tall NUC 15 Pro. See ASUS NUC 16 Pro vs NUC 15 Pro and ASUS NUC 15 Pro vs Pro+.
Buying in Singapore
SourceIT supplies the NUC 15 Pro Slim Core Ultra 5 225H barebone (S$686.22), Slim Core Ultra 7 255H barebone (S$821.72), Tall Core Ultra 5 225H barebone (S$642.07), Tall Core Ultra 7 255H barebone (S$749.25) and the ready-to-use NUC 15 Pro Tall Core Ultra 5 225H, 16GB, 512GB, Windows 11 Pro (S$1,363.06), all listed 3 Nov 2026. Whether to buy a barebone or a full system is covered in ASUS NUC Barebone vs Ready-to-Use PC. Browse the ASUS NUC collection. For a quotation or to check expansion options, use Request for Quotation on the product page, call (65) 6978 3502, email Sales@sourceit.com.sg or use our contact page.
Frequently asked questions
Does the ASUS NUC 15 Pro Tall have a 2.5-inch drive bay? No. ASUS's NUC 15 Pro spec page lists no 2.5-inch bay for either the Slim or the Tall. The NUC 14 Pro Tall had one.
What is the size difference between NUC 15 Pro Slim and Tall? Both are 117 x 112 mm. The Slim is 36.8 mm high and the Tall is 54 mm, according to ASUS.
Do Slim and Tall have different processors or ports? No. ASUS lists the same processor range and the same ports for both, including two Thunderbolt 4, two HDMI 2.1 and one 2.5GbE port.
What can I add to the Tall chassis? Reviewers report optional expansion for the Tall, such as a second M.2 2280 slot, a second 2.5GbE port or LAN plus RS232. ASUS's spec page does not list these, so check availability with us before ordering.
Which is cheaper at SourceIT? The Tall. On 3 Nov 2026 the Core Ultra 5 225H barebone was S$642.07 in Tall and S$686.22 in Slim.
SourceIT Approved
Researched and verified by the SourceIT team for Singapore buyers.
