# Fanxiang S660 512GB Review — Budget PCIe 4.0 with QLC Limits (2026)

The Fanxiang S660 512 GB is the cheapest ticket into the PCIe 4.0 club — a DRAM-less QLC drive that reads fast but writes like a hard drive once its cache folds, and at this capacity the trade-offs stack up quickly.

Quick answer: The Fanxiang S660 512 GB makes sense only as the cheapest possible PCIe 4.0 boot drive for a secondary or budget system where every dollar counts and no important data lives on the drive without a backup. For anything else — a primary system drive, a laptop with irreplaceable files, or any workflow involving regular large transfers — spend the modest premium for a Crucial P3 Plus or Team Group MP44Q. The S660's single-sided PCB and included heatsink are nice touches, but they do not compensate for QLC write cliffs and a warranty that exists mostly on paper.

## Specifications

| Specification | Value |
| --- | --- |
| Capacity | 512 GB |
| Interface | M.2 4.0 x 4 |
| Controller | Phison PS5021-E21T 4 Channel |
| Memory type | Micron 176-L QLC |
| DRAM cache | No |
| Sequential read | 5000 MB/s |
| Sequential write | 4500 MB/s |
| Random read IOPS | 600000 |
| Random write IOPS | 500000 |
| Endurance | 400 TBW |
| MTBF | 1500000 |
| Warranty | 5 years |

## Performance

Rated sequential speeds are 5,000 MB/s reads and 4,500 MB/s writes, though at 512 GB the write figure may be lower in practice due to reduced NAND parallelism. Random IOPS are in the range of 600,000 reads and 500,000 writes — adequate for boot and gaming use but well below DRAM-backed drives in the same interface class.

The defining performance characteristic of the S660 is its post-cache write behaviour. The drive uses a pseudo-SLC cache to hit rated speeds, but once that cache fills — which happens faster on a 512 GB drive with less free NAND to allocate as cache — write speeds collapse to roughly 1,400 MB/s in the folding phase and eventually settle around 530 MB/s at native QLC speed. That is SATA territory. For a boot drive or a game library where writes are mostly small and bursty, this is rarely noticeable. For anyone who regularly moves large files, the S660 at 512 GB is the wrong tool.

## Endurance, TBW & Warranty

Fanxiang claims a 5-year warranty on the S660, though the drive is not even listed on the company's official website. The 512 GB endurance rating is not published, but based on the 4 TB model's confirmed 2,800 TBW, this capacity should carry roughly 400 TBW. At a typical 20 GB per day, that yields over 50 years of writes — QLC endurance concerns are largely theoretical for light consumer workloads. The practical warranty issue, as with all Fanxiang products, is whether anyone at the company will actually process your claim. Multiple user reviews report two S660 drives failing within 40 hours of use with no manufacturer response.

## Pros and Cons

**Pros:**

- 5,000 MB/s PCIe 4.0 reads at a very low entry price
- Single-sided PCB fits thin laptops and PS5
- Includes heatsink and mounting hardware in the box
- 5-year warranty period on paper
**Cons:**

- QLC NAND with severe post-cache write drop to ~530 MB/s
- DRAM-less HMB design struggles under sustained mixed I/O
- Marketed as TLC on some store listings but confirmed QLC via Flash ID
- Warranty support is practically non-existent per user reports
- 512 GB capacity has reduced NAND parallelism — writes likely below rated spec


## Verdict

The Fanxiang S660 512 GB makes sense only as the cheapest possible PCIe 4.0 boot drive for a secondary or budget system where every dollar counts and no important data lives on the drive without a backup. For anything else — a primary system drive, a laptop with irreplaceable files, or any workflow involving regular large transfers — spend the modest premium for a Crucial P3 Plus or Team Group MP44Q. The S660's single-sided PCB and included heatsink are nice touches, but they do not compensate for QLC write cliffs and a warranty that exists mostly on paper.

## Frequently Asked Questions

### Does the Fanxiang S660 have a DRAM cache?

No. The S660 is a DRAM-less design that uses Host Memory Buffer (HMB) to borrow 64 MB of system RAM for its mapping table. This is standard for budget PCIe 4.0 drives — the Crucial P3 Plus uses the same E21T controller with the same approach — but it means random I/O consistency and sustained mixed-workload performance will fall behind DRAM-backed alternatives under heavy use.

### Is the Fanxiang S660 512GB good for gaming?

For game loading and texture streaming, the 5,000 MB/s reads are more than sufficient — you will not notice a difference versus a faster drive in real-world game load times. The limitation is capacity: 512 GB fills up quickly with modern game installs, and the QLC write cliff means downloading or moving large game files will be noticeably slow once the cache exhausts. As a secondary game drive where writes are infrequent, it works. As a primary everything drive, 512 GB is cramped and the QLC penalty shows.

### Is the Fanxiang S660 512GB compatible with the PS5?

The S660 meets the PCIe 4.0 x4 and M.2 2280 form factor requirements, and its single-sided PCB with included heatsink is a good physical fit for the PS5 bay. However, at 5,000 MB/s reads it falls below Sony's 5,500 MB/s recommended floor. The PS5 will still accept and format the drive, but some games may exhibit longer load times or streaming hitches. For PS5 expansion, the 1 TB or larger S660 capacities that maintain the full 5,000 MB/s read rating are a better match.

### What is the TBW endurance of the Fanxiang S660 512GB?

Fanxiang does not publish a capacity-specific TBW for the 512 GB model. Scaling from the 4 TB variant's confirmed 2,800 TBW rating, the 512 GB endurance is estimated at roughly 400 TBW. At a light consumer workload of 20 GB per day, that endurance budget lasts over 50 years — QLC write endurance is not the practical limitation at this capacity for typical use.

### Does the Fanxiang S660 need a heatsink?

The E21T controller is relatively power-efficient compared to 8-channel designs, and the single-sided PCB concentrates heat on one side only. Fanxiang includes a heatsink in the box, and in a desktop with decent airflow the drive can operate without throttling even without it. Inside a PS5 or a cramped laptop, however, ambient temperatures are higher and the included heatsink becomes important for sustained performance.

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Last updated: 2026-08-10. Source: https://ssdrive.net/fanxiang-s660-512-gb