ASUS ExpertBook B9 vs ThinkPad X1 Carbon: Who Builds the Better Lightweight Business Laptop?
For 2026 builds, the ASUS ExpertBook Ultra, the successor to ASUS's B9 flagship, gives you more battery and a richer OLED screen for a lot less money. The ThinkPad X1 Carbon Gen 14 is still slightly lighter, has an extra Thunderbolt port and has a stronger repairability record. On SourceIT's 4 Nov 2026 listings, the ASUS ExpertBook Ultra (B9406CAA) with Core Ultra 7 356H, 32GB, 1TB and a 2.8K OLED touch screen is S$4,303.20. The ThinkPad X1 Carbon Gen 14 with Core Ultra 7 355, 32GB and 1TB is S$6,757.86, a difference of S$2,454.66. If you can accept last year's chip, the ThinkPad X1 Carbon Gen 13 with Core Ultra 7 258V, 32GB and 1TB at S$3,245.00 is S$1,058.20 cheaper than the Ultra.
Where did the ExpertBook B9 go?
ASUS's ultralight business flagship used to be the ExpertBook B9, most recently the B9 OLED (B9403) with a magnesium-lithium chassis. At CES 2026 ASUS replaced it with the ExpertBook Ultra, model code B9406CAA. ASUS's Singapore site lists the Ultra from S$3,099 to S$5,399 and SourceIT's listings use the Ultra name. The B9 OLED B9403 is not in stock at SourceIT, so this comparison uses the Ultra.
How do they compare?
| ASUS ExpertBook Ultra (B9406CAA) | ThinkPad X1 Carbon Gen 14 | ThinkPad X1 Carbon Gen 13 | |
|---|---|---|---|
| Example SourceIT price | S$4,303.20 (U7-356H, 32GB/1TB, OLED); S$6,643.20 (X9 vPro 388H, 64GB/1TB, tandem OLED) | S$6,757.86 (U7-355, 32GB/1TB); S$8,577.42 (U7-365, 64GB/1TB) | S$3,245.00 (U7-258V, 32GB/1TB) |
| Starting weight | from 0.99 kg (Notebookcheck measured 1.111 kg) | from 0.977 kg | from 0.986 kg (258V) |
| Chassis | Magnesium-aluminium | Carbon-fibre top; magnesium or aluminium bottom | Carbon-fibre top; magnesium or aluminium bottom |
| Battery | 70Wh; ASUS claims up to 26 hours | 58Wh | 57Wh |
| Memory | Soldered LPDDR5X, not upgradeable | Soldered LPDDR5X, not upgradeable | On-package LPDDR5X, not upgradeable |
| Ports | 2x Thunderbolt 4, 2x USB-A, HDMI 2.1; no Ethernet | 3x Thunderbolt 4, 1x USB-A, HDMI 2.1 | 2x Thunderbolt 4, 2x USB-A, HDMI 2.1 |
| Durability claim | MIL-STD-810H (24 procedures) | "MIL-STD-810H military test passed" | "MIL-STD-810H military test passed" |
| Warranty on linked listing | 3 years onsite, next business day; battery 3 years | No term stated; check the listing | 3 years onsite |
From ASUS's ExpertBook Ultra spec page (Singapore), Lenovo PSREF for the ThinkPad X1 Carbon Gen 14 Aura Edition (23 Oct 2026) and Gen 13 (10 Jun 2025), and Notebookcheck's ExpertBook Ultra review (27 Jan 2026). Prices and warranty are as stated on SourceIT listings on 4 Nov 2026. We have not tested these laptops ourselves.
Which is lighter and better built?
On paper the two are within a few grams. Lenovo quotes the X1 Carbon Gen 14 from 0.977 kg and ASUS quotes the Ultra from 0.99 kg. Notebookcheck weighed its Ultra review unit, a Core Ultra X7 358H with 32GB, at 1.111 kg. SourceIT's listings with the 120Hz tandem OLED panel say "from 1.10 kg", so expect the better-specified versions to weigh more than 1 kg. The materials take different routes. ASUS uses an "aviation-inspired" magnesium-aluminium body with a nano-ceramic coating, while Lenovo combines a carbon-fibre lid with a magnesium or aluminium base.
Both claim MIL-STD-810H. ASUS describes "24 rigorous durability tests" for the Ultra, and Lenovo says ThinkPads are tested to 12 methods and 26 procedures. Neither publishes hinge or keystroke counts for these models. Notebookcheck rated the Ultra 88% but found a weak hinge on its pre-retail unit, which ASUS said it would fix. TechRadar gave it 4.5/5 and listed price, no upgrades and few ports as the downsides.
The X1 Carbon is the lighter, more repairable laptop. The ExpertBook Ultra is the better-equipped one per dollar. Executives who carry a laptop all day will feel the battery difference more than the weight difference.
Where does the ExpertBook Ultra win?
- Price. With 32GB and 1TB, it is S$2,454.66 cheaper than the X1 Carbon Gen 14 Core Ultra 7 355. With 64GB, the Ultra's Core Ultra X9 vPro 388H build at S$6,643.20 is S$1,934.22 cheaper than the X1 Carbon Gen 14 Core Ultra 7 365 at S$8,577.42.
- Battery. 70Wh against 58Wh in the X1 Carbon Gen 14, about a fifth more capacity at a similar weight. ASUS claims up to 26 hours; independent runtimes vary with the screen.
- Screen. Every Ultra at SourceIT has a 2.8K OLED touch screen, and the tandem OLED versions run at 120Hz and 600 nits (listing figures).
- AI features. ASUS lists a 50 TOPS NPU (47 TOPS on the Core Ultra 5 325), making the Ultra a Copilot+ PC, and bundles its MyExpert AI tools on 2026 models.
- Written battery cover. The Ultra listings state 3 years onsite, next business day, with a 3-year battery warranty.
Where does the X1 Carbon win?
- Repairability. Windows Central reported a 9/10 repairability score for the X1 Carbon Gen 14, with replaceable USB ports, battery, keyboard, speakers and fans. Notebookcheck found the Ultra uses soldered memory, a single M.2 slot and a non-removable Wi-Fi card, behind 10 T5 Torx screws.
- Connectivity. Three Thunderbolt 4 ports on the Gen 14 against two on the Ultra. Neither has Ethernet. Plan for a dock or adapter, as explained in Is Your Office Ready for Laptops That Have No Ethernet Port?.
- Budget option. The X1 Carbon Gen 13 with a Core Ultra 7 258V, 32GB and 1TB is S$3,245.00 with 3 years onsite stated on the listing. If last year's Lunar Lake chip is enough, it is S$1,058.20 below the cheapest Ultra.
- Track record. The X1 Carbon has more than a decade of fleet history, and Lenovo publishes full PSREF spec sheets for every configuration.
Neither laptop lets you add memory later, so buy the memory you will need for the laptop's whole life. Our soldered RAM and X1 Carbon RAM limits guides explain the trade-off. If 32GB is a stretch, compare the X1 Carbon against Lenovo's own T14 in ThinkPad X1 Carbon vs T14. For travel-specific durability, see Your Laptop Travels More Than You Do. Is It Tough Enough?.
Buying in Singapore
SourceIT stocks the ASUS ExpertBook Ultra B9406CAA Core Ultra 7 356H, 32GB, 1TB (S$4,303.20), the ExpertBook Ultra with tandem OLED 120Hz (S$4,490.40), the ExpertBook Ultra Core Ultra X9 vPro 388H, 64GB, 1TB (S$6,643.20), the ThinkPad X1 Carbon Gen 14 Core Ultra 7 355, 32GB, 1TB (S$6,757.86), the X1 Carbon Gen 14 Core Ultra 7 365, 64GB, 1TB (S$8,577.42) and the X1 Carbon Gen 13 Core Ultra 7 258V, 32GB, 1TB (S$3,245.00), all listed 4 Nov 2026. Browse the ASUS Laptops and ThinkPad X1 Carbon collections, and the ASUS docking stations for wired networking at the desk. For a quotation, 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
Is the ASUS ExpertBook Ultra the same as the ExpertBook B9? It is the B9's successor. ASUS launched the ExpertBook Ultra (model code B9406CAA) at CES 2026 as its new ultralight business flagship, replacing the B9 OLED line.
How much cheaper is the ExpertBook Ultra than the X1 Carbon Gen 14? On SourceIT's 4 Nov 2026 listings, S$2,454.66 cheaper with 32GB and 1TB (S$4,303.20 vs S$6,757.86), and S$1,934.22 cheaper with 64GB and 1TB (S$6,643.20 vs S$8,577.42).
Which is lighter? Lenovo quotes the X1 Carbon Gen 14 from 0.977 kg and ASUS quotes the ExpertBook Ultra from 0.99 kg. The tandem OLED Ultra versions are listed from 1.10 kg.
Can I upgrade the RAM on either laptop? No. Both solder their memory to the board, so order the capacity you will need for the laptop's whole life.
Does the ExpertBook Ultra have an Ethernet port? No, and neither does the X1 Carbon. Use a USB-C dock or adapter for wired networking.
SourceIT Approved
Researched and verified by the SourceIT team for Singapore buyers.
