04/08/2026 2:25 am
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Im losing my mind trying to figure out the hardware requirements for running DeepSeek V4 Flash locally. Im in a tight spot because I need to get this set up for some local dev work by next month and my desk space is super limited. Im basically stuck between two options right now: picking up a used Mac Studio with the M2 Ultra or building a custom rig with dual 3090s. My logic was that the VRAM on the Mac would be safer, but building a PC is way cheaper. Does the V4 Flash actually run okay on 48GB VRAM or am I gonna run into major OOM errors constantly? Seriously need a sanity check here.
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11
04/08/2026 3:00 am
Just catching up on this thread. Honestly, I really wanted the M-series chips to be the holy grail for local LLMs, but my experience with a Apple Mac Studio M2 Ultra 128GB Unified Memory has been a bit of a letdown. While the unified memory seems perfect on paper, the memory bandwidth throttling just kills the token generation speeds when you start pushing larger contexts. It is not nearly as snappy as what you get with raw CUDA power. I actually moved away from the Mac setup for my daily driver because of this. If you are dead set on running DeepSeek, here is what I have learned through trial and error:
- The 48GB VRAM limit on a dual NVIDIA GeForce RTX 3090 24GB GDDR6X setup is decent, but quantization is key. You will need to look into llama.cpp or ExLlamaV2 to manage the overhead.
- Check out the leaderboard over at Hugging Face Open LLM Leaderboard to track how different quant levels affect your VRAM usage.
- Using something like Ollama or LM Studio can help you monitor your VRAM usage in real-time, which might save you from constant OOM crashes. Unfortunately, building the PC is messy and hot, but it is way faster for local dev work. If I could do it again, I would skip the Mac route and just optimize my model loading strategy on the PC build. It is not as polished, but the performance per dollar is just unbeatable.
10
04/08/2026 2:26 am
Go for the dual NVIDIA GeForce RTX 3090 24GB GDDR6X. 48GB total is plenty and honestly beats the Mac for inference speed. No complaints here, it works well.
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04/08/2026 3:10 am
Stumbled upon this thread today and figured I would chime in. Honestly, I totally get the stress about the VRAM limits. I went down a rabbit hole trying to run these larger models on a custom build last year. IIRC, 48GB is kind of the bare minimum if you want to keep the context window usable without things crawling to a halt. I was pretty worried about OOM errors too, but after tuning my quantization settings, it actually works well enough for my dev workflows. Not sure if V4 Flash is gonna be perfectly happy there, but I suspect it'll fit if you're willing to sacrifice a little precision. Building is definitely more of a headache than buying a pre-made box, but being able to swap out parts when things get dated is worth the effort imo. Just make sure your cooling is solid if you shove two cards in there.
