SK Hynix
Laptop Memory Module HMA851S6JJR6N-VK Compatible Replacement Spare Part for SK Hynix HMA851S6JJR6N 4GB 1RX16 DDR4 SO-DIMM PC4-21300 2666MHz 260-pin Non-ECC CL19 1.2V
Available Styles / Variations:
Limited Entry-Level Capacity
Validated by C.R. Vinoth Kumar ยท Founder & Senior Editor
8GB of total memory is extremely marginal in 2026. Windows 11 uses 3-4GB at idle, leaving very little headroom for multitasking or gaming. We highly recommend upgrading to at least 16GB, or 32GB to prevent page-file stutters.
Current price
$41.99$10.50/GBAs of May 30, 2026 ยท Verify on Amazon ยท Price subject to change
$/GB vs DDR4 market avg
Near avgDeal score
57/100
At $10.50/GB โ DDR4 market rate.
Good time to buy
Price is near its tracked low of $41.99 โ in the bottom 20% of its recorded range.
Verify Alternative Stores
Our systems refresh prices daily from Amazon.com to secure the absolute lowest USD market rate. You can cross-reference this RAM kit (ASIN: B09FLWJQPP) against alternative marketplaces like Newegg or Crucial before buying.
Product prices and availability are accurate as of the date of the last daily update and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply to the purchase of this product. As an Amazon Associate we earn from qualifying purchases.
At a Glance
Strengths
- Price near its tracked low of $41.99
Limitations
- Limited review data โ only 1 Amazon reviews
- Availability unconfirmed โ may be out of stock or delisted
All points are derived from price data, customer ratings, and product specifications โ not editorial opinion. Updated daily.
Is This RAM Right for You?
Based on 4GB DDR4 SO-DIMM specifications.
Laptop RAM โ suitable for gaming laptops with compatible slots
4GB is below the recommended minimum for comfortable everyday use
4GB is insufficient for video editing or 3D rendering workloads
SO-DIMM laptop RAM is not used in servers โ servers require DIMM or RDIMM modules
SO-DIMM form factor โ correct type for laptop memory upgrades. Verify your laptop has an accessible slot.
Verdicts based on capacity, form factor, and ECC specifications โ not editorial opinion. Capacity recommendations reflect 2026 software requirements.
Price History
Updated daily โ track price trends over time
Current
$41.99
38d Low
$41.99
38d High
$42.00
38d Avg
$41.99
Price Range
Tracked low
$41.99Current
$41.99Tracked high
$42.00โ Near tracked low
Speed Ranking
Top 46%
2666MHz ranks in the top 46% of all DDR4 speeds tracked (1,546 modules).
Z-Score Deviation
Fair / Average Price
Deviation: -0.39ฯ
This product is currently priced within normal historical margins.
Specifications
Memory TypeDDR generation (DDR4 vs DDR5) ยท guide | DDR4 |
CapacityTotal kit memory size ยท guide | 4GB |
SpeedFrequency in MT/s or MHz ยท guide | 2666MHz |
CAS LatencyClock cycles response delay ยท guide | CL19 |
True LatencyAbsolute nanosecond latency | 14.25 ns(High latency)= (19 ร 2000) รท 2666 |
Form FactorDIMM (Desktop) vs SO-DIMM (Laptop) ยท guide | SO-DIMM |
VoltageOperating voltage level | 1.2V |
ASIN | B09FLWJQPP |
Spotted a wrong price or spec? Report a data correction ยท How we verify data
Compatible Platforms
Always verify with your motherboard's QVL before purchasing.
Cheaper Alternatives
Same 4GB DDR4 โ lower $/GB than this product
SK Hynix
4GB 1Rx8 PC4-17000 DDR4-2133 1.2volt CL15 260 Pin Sodimm Memory p/n HMA451S6AFR8N-TF48% cheaper/GB
SK Hynix
4GB DDR4 3200MHz PC4-25600 1.2V 1R x 16 SODIMM Laptop RAM Memory Module HMA851S6CJR6N-XN, OEM Package47% cheaper/GB
Samsung
Samsung 4GB DDR4 SODIMM RAM Module 3200MHz 1Rx16 PC4-3200AA 260-Pin SDRAM Laptop Memory M471A5244CB0-CWE43% cheaper/GB
Ranked by lowest $/GB. Same 4GB DDR4 SO-DIMM only. Prices updated daily.
DDR4 Price by Capacity
Average $/GB across all DDR4 modules in the database
| Capacity | Avg $/GB |
|---|---|
| 4GBThis product | $10.56/GB |
| 8GB | $9.68/GB |
| 16GB | $9.70/GB |
| 32GB | $9.02/GB |
| 64GB | $8.97/GB |
| 128GB | $6.58/GB |
Upgrade Cost Calculator
How much more (or less) would you spend to step up or down in capacity? Prices shown are the cheapest available DDR4 SO-DIMM in each tier today.
Current
4GB
$41.99$10.50/GBPrices are the lowest available in each tier from our daily database โ verify on Amazon before purchasing. Only DDR4 SO-DIMM modules compared.
Also available from SK Hynix
Same brand, different configurations
SK Hynix
Hynix 8GB PC4-21300 DDR4-2666MHz 260-Pin SODIMM 1.2V Single Rank Memory Module HMA81GS6CJR8N-VK
SK Hynix
32GB KIT (2x16GB) DDR4 2666MHz (PC4-2666V) PC4-21300 SODIMM Laptop RAM รขโฌโ 260-Pin 1.2V CL19 Non-ECC Unbuffered Memory Module for Laptop, Notebook, Mini PC, All-in-One
SK Hynix
16GB 2RX8 DDR4 SO-DIMM PC4-21300 2666MHZ Memory Module HMA82GS6JJR8N-VK
Related pages
Frequently Asked Questions
Is the SK Hynix 4GB 2666MHz DDR4 compatible with my motherboard?
This module is compatible with Laptop โ DDR4 SO-DIMM. Always verify with your motherboard's QVL (Qualified Vendor List) before purchasing, as compatibility can vary by board revision.
Is this DDR4 module a good deal right now?
At $41.99, this module is near its tracked price low of $41.99 โ historically a good time to buy. Check the price history chart above for context. Prices are updated daily from Amazon.
What is 2666MHz RAM used for?
DDR4 RAM is used in Intel LGA1200/LGA1700 and AMD AM4 (Ryzen 1000-5000) systems. It offers excellent value for existing platforms. 2666MHz is a standard DDR4 speed tier.
How does SK Hynix RAM compare to other brands?
SK Hynix has 178 modules tracked with an average customer rating of 4.5โ . Browse all SK Hynix modules or use the comparison tool to see how it stacks up against Corsair, G.Skill, Kingston, and Crucial.
Is 16GB of RAM enough for gaming in 2026?
4GB is below the 16GB minimum recommended for gaming in 2026. Most modern AAA titles require 12โ16GB. Consider upgrading to at least 16GB for a smooth gaming experience.
What is the difference between a single 4GB stick and a 2ร2GB kit?
A single 4GB stick runs in single-channel mode, using only one memory channel. A 2ร2GB kit of the same total capacity runs in dual-channel mode, doubling memory bandwidth and improving real-world performance by 10โ30%. For best performance, always buy RAM in matched pairs.
Similar DDR4 RAM
Samsung
Samsung 4GB DDR4 SODIMM RAM Module 3200MHz 1Rx16 PC4-3200AA 260-Pin SDRAM Laptop Memory M471A5244CB0-CWE
Timetec
Timetec DDR4-2666 4GB Replacement for Synology D4NESO-2666-4G Non-ECC Unbuffered SODIMM (Compatible for RS820RP+, RS820+, DS920+, DS720+, DS420+, DS220+, DS2419+, DS2419+II, DS1819+, DVA3219, DS1618+)
Expertly Curated by C.R. Vinoth Kumar
Lead Hardware AnalystC.R. Vinoth Kumar is a senior systems systems engineer and memory hardware architect with over 12 years of experience benchmarking computer components, building performance virtualization servers, and assembling local LLM inference rigs. Every memory module tracked in our database is mathematically checked using custom telemetry to isolate nanosecond CAS latency bounds, price-per-gigabyte market averages, and Ryzen/Intel platform pairings.
As an Amazon Associate we earn from qualifying purchases. Prices are updated daily and may change on Amazon.