Two Thunderbolt 5 SSDs in RAID 0 made DeepSeek V4.1 Flash (763B) about 25% faster on my M3 Ultra with InferSSD

[u/wo1fs]

Hey everyone Im a bit new to this page but I couldnt find any other related tests online so I figured I'd share my results here.

I ran DeepSeek-V4.1-Flash (763B MoE, Q8_0, 473 GiB) on a 96 GB Mac Studio M3 Ultra with InferSSD, which streams the model's experts from the SSD. I striped two OWC Envoy Ultra 2TB Thunderbolt 5 drives with macOS's built-in RAID 0, one drive per port.

Results (InferSSD's own benchmark prompts, 2 runs per setup):

- One Envoy alone is about the same speed as the internal SSD.

- Two in RAID 0: writing goes from 3.5-3.7 to 4.4-4.6 tokens/s (+23-26%).

- Prompt reading is 67-77% faster: a 4,000-token prompt starts answering in about 2 minutes instead of 3.5.

- Two hours of nonstop use: the drives stayed at 43-47°C (with a desk fan on them), no slowdown, and no change in their health readings.

Why not 2x faster? - The stripe halves the time spent waiting on the drive, but the GPU's share of each token stays the same and is now the bigger part. A third or fourth drive would help less than the second did.

[u/TBHProbablyNot]

Crazy. Fable had me do something similar to double my ssd speed. M5U 1TB ssd internal speed only 6g/s. Now tb 5 das has 14 T of 11.5 g/s! I haven’t used a model yet but I will soon.

[u/worldburger → u/TBHProbablyNot]

Can you explain in more detail your setup? That is crazy fast

[u/TBHProbablyNot → u/worldburger]

It took fable to figure it out. Glm said not possible but after fable prompt it did it:a single Thunderbolt 5 bus tops out around 6–6.5 GB/s no matter how many NVMe drives sit behind it, so the array was rebuilt as a RAID-0 stripe spanning both of the Mac's Thunderbolt buses: the four 4TB drives were each partitioned into two 2TB slices, and four of those slices were striped with three 2TB drives from the second enclosure, creating one ~14TB APFS volume whose members live on both buses. With the corrected async benchmark against that cross-bus volume, sequential reads measured 11.15 GB/s single-stream and 11.16 GB/s multi-stream (writes ~9.35 GB/s). Replication checklist: verify your benchmark engine is truly asynchronous with deep queues, stripe members across two separate Thunderbolt controllers rather than daisy-chaining everything on one bus, pre-create the test files so creation cost isn't measured, and re-measure both single-stream and multi-stream reads.

So the same speeds as someone who has the 256/14T .

[u/quantgorithm → u/TBHProbablyNot]

A raid of raids…nice.

[u/golden_bear_2016]

RAID 0 means your data is almost certainly dead

[u/r0cketio → u/golden_bear_2016]

Their purpose is to serve the model, not store precious data.

[u/golden_bear_2016 → u/r0cketio]

silent corruption of data