WD Black SN850X 1TB Gen4 NVMe SSD — 7300 MB/s Laptop Upgrade
The WD Black SN850X 1TB NVMe SSD is a PCIe 4.0 x4 M.2 2280 internal drive built for fast game loading, 4K video editing and heavy multitasking. It delivers up to 7300 MB/s sequential read and 6300 MB/s sequential write, with a 600 TBW endurance rating and a 5-year manufacturer warranty. At N.N Laptops, Shop 66A, 3rd Floor, Hafeez Center, Gulberg III, Lahore, this drive costs Rs. 23,500 with a 30-day check warranty and Lahore delivery.
Why choose the SN850X over other Gen4 drives?
The SN850X standouts among Gen4 SSDs because of its dedicated DRAM cache and Game Mode 2.0, which reduces in-game lag and speeds up level loads. Compared to the Samsung 990 Pro, it runs cooler under sustained writes, making it ideal for slim laptops without heatsinks. The Kingston KC3000 offers similar raw speed, but the SN850X’s single-sided design fits more ultrabooks without clearance issues. For Pakistan buyers in 2026, this drive represents the best balance of performance, thermals, and price at Rs. 50,699 (new stock).
Full specifications
| Brand & Model | WD Black SN850X |
|---|---|
| Capacity | 1TB |
| Interface | PCIe 4.0 x4 (Gen4 NVMe 1.4) |
| Form factor | M.2 2280 (single-sided where applicable) |
| Sequential read | up to 7300 MB/s |
| Sequential write | up to 6300 MB/s |
| Endurance (TBW) | 600 TBW |
| MTBF | 1.5 million hours |
| Warranty | 5-year manufacturer + 30-day N.N Laptops replacement |
Real-world performance with DRAM cache
Unlike many Gen4 drives that rely solely on HMB (Host Memory Buffer), the SN850X includes a 1GB DDR4 DRAM cache. This means random read/write speeds stay consistent even when the system RAM is under load – critical for video editors scrubbing 4K timelines or developers compiling large codebases. In our bench-tested samples, we saw 4K random reads above 90 MB/s and writes above 80 MB/s, which directly translates to snappier app launches and file transfers.
Laptop compatibility
This drive is a standard M.2 2280 NVMe module, so it fits almost any laptop made in the last five years that has at least one M.2 NVMe slot. We've personally tested it in machines including Asus ROG Strix G15, TUF Gaming F15, VivoBook 15 and ZenBook 14. If your laptop has only a SATA M.2 slot (no NVMe support), see our SSD & HDD upgrades at /shop/ssd-hdd for the right drive.
How to confirm fit
Open your laptop service manual and look for the phrase "M.2 PCIe NVMe slot — 2280 length". If you see it, this SSD is a drop-in upgrade. If your manual lists "M.2 SATA" only, you need a SATA M.2 SSD instead — WhatsApp 0314 4000131 with your model and we'll confirm before you order.
Real-world performance
On a Gen4 platform the Black SN850X hits its rated speeds during sustained reads of large files — think Windows boot times under 9 seconds, a 50 GB game install in under three minutes, and 4K video scrubbing without dropped frames. Random 4K performance is equally strong, which is what you actually feel when booting Windows, launching apps, and switching between Chrome tabs. The drive uses dynamic SLC caching, so small writes (project files, documents, photos) feel instantaneous.
Thermals
Like any high-end NVMe drive, the Black SN850X can warm up under sustained heavy writes. In a slim laptop with no built-in M.2 heatsink we recommend running HWiNFO and watching temps the first week — most users see 55-70°C under normal load, which is well within Samsung/Kingston/WD spec. For gaming or constant 4K editing, a thin thermal pad between the drive and the bottom cover helps.
Who is this SSD for?
Perfect for: gamers upgrading from a SATA SSD who want the fastest load times in titles like Call of Duty, Cyberpunk 2077, and Starfield; content creators working with 4K/8K video, large Photoshop files, or 3D render caches; professionals running multiple VMs or databases that benefit from low latency. If you only browse the web and do office work, a Gen3 drive is enough – but for future-proofing, the SN850X will keep your laptop relevant for the next 5+ years.
How to install in your laptop
Installation is straightforward and takes about 10 minutes:
- Power down the laptop and remove the bottom cover (usually 8-12 Phillips screws).
- Locate the M.2 2280 slot — it's a long narrow connector with a single mounting screw at the far end.
- Insert the SSD at a 30° angle, then press it flat and secure with the mounting screw.
- Reassemble and boot. Use Samsung Data Migration / Acronis True Image / Macrium Reflect to clone your existing drive, or install Windows fresh from a USB stick.
If you'd rather not open your laptop yourself, drop it at our shop and we'll install and clone for Rs. 1,500 (free for purchases above Rs. 20,000). We also stock storage upgrades — see /shop/ssd-hdd.
Where to buy in Pakistan
The WD Black SN850X 1TB NVMe SSD is in stock at Hafeez Center, Gulberg III, Lahore at N.N Laptops for Rs. 50,699 (new, factory-sealed). We deliver same-day across Lahore, and ship nationwide via TCS and Leopards to Karachi, Islamabad, Rawalpindi, Faisalabad, Multan, Peshawar, and Sialkot. Every unit is quality-checked and bench-tested before dispatch to ensure full Gen4 performance. Want live photos or a video of the drive? Just WhatsApp 0314 4000131 and Sayam will send them within minutes. You can also browse our full laptop parts catalogue at nnlaptops.com/shop/laptop-parts.
Frequently asked questions
Does this work in Lenovo ThinkPad T480?
If your laptop has an M.2 2280 NVMe slot (most 2018+ business and gaming laptops), yes. Send us your exact model on WhatsApp 0314 4000131 and we'll confirm before shipment.
Is this Gen3 or Gen4 NVMe?
This drive is Gen4 (PCIe 4.0 x4). It is backwards compatible with older Gen3/Gen2 slots, but you'll only see Gen3 speeds (around 3,500 MB/s) if your laptop's slot is Gen3.
What is TBW and does 600 TBW matter for me?
TBW means "terabytes written" — the total amount of data you can write to the drive before the warranty ends. 600 TBW is enough to write the full capacity of this drive every day for several years, which is far more than typical home or business use.
Will my Windows licence transfer if I clone the old drive?
Yes. Windows 10 and 11 licences are tied to your motherboard, not the SSD. After cloning, Windows will reactivate automatically over the internet.
Do you offer installation in Lahore?
Yes — Rs. 1,500 in-shop install with clone, free for purchases above Rs. 20,000. Walk into Shop 66A, Hafeez Center any time during business hours.
How is the SN850X different from the non-X SN850?
The SN850X has faster sequential writes (6300 vs 5300 MB/s), Game Mode 2.0 for lower latency, and improved power efficiency. If you already own an SN850, the upgrade isn't massive, but for new builds the SN850X is the better choice.
