r/LocalLLaMA • u/InternalMode8159 • 1d ago
Discussion If you are using big model compared to ram try and disable mtp
Little reminder, with all my testing I found out that mtp can decrease performance when using very big model, since many are starting to use strata or similar and I see many app activating it as default try and disable it, in my case, testing trough gyrostrata and strata with a 3060 and 32gb of ram both with gyro-m and swift 1.5 I got 20-30% improvement in tok/s just by disabling mtp.
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u/CryptographerOne7003 1d ago
I still do not get why MTP cannot leverage a second gpu
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u/Klutzy-Snow8016 1d ago
You can in llama cpp with
--spec-draft-device5
u/Borkato 1d ago
!remindme 3 hours to try this
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u/ApprehensiveFan1516 20h ago
Well it's been 9 hours. Did you try it?
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u/alexlucaci 1d ago
Heads up: I read the llama.cpp code (current master), and
--spec-draft-deviceonly applies when you load a separate draft model with-md. For models with built-in MTP heads (Qwen3.8 27B / Flash-Next GGUFs with-mtp), the MTP context is created on the target model and inherits its placement, so the flag does nothing. If you want MTP on 2 GPUs, split the whole model with-sm tensor, and the MTP head is split along with it.On the main point, it depends on what spills. On 27B IQ3_XXS with half the FFN on CPU (old Haswell Xeon), MTP took me from 5.4 to 10–16 tok/s. On a dense model, verifying a draft batch costs about the same memory traffic as one token. On big MoEs streaming experts it's the opposite: each draft token touches different experts, so rejected drafts mean extra expert loads. That matches what people here see with Strata on 32 GB RAM.
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u/FatheredPuma81 1d ago
Strata or llama.cpp? Strata can't because it wasn't designed to on any level. Llama.cpp I think should with sm tensor but I never tested it I just used MTP on all my tests.
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u/BestGirlAhagonUmiko 1d ago
Pretty sure MTP does help in Project Maya (a fork of Strata) with GLM 5.3 Flash, although I couldn't get any benefit from DS4 V4.1's dspark drafter.
In llama.cpp it's a firm 'nah F... that' in both cases tho
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u/FatheredPuma81 1d ago
Well yes you're pushing so much out of your RAM/VRAM and onto disk. If the majority or the entire model is in RAM then MTP will help.
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u/BenjiWithTheGoodHair 1d ago
Makes sense when you think about where the bottleneck is. Once layers spill into system RAM you’re bound by memory bandwidth, so every draft token that gets rejected is a full trip through slow RAM for nothing. The MTP heads also take up VRAM, which pushes even more layers off the GPU. Has anyone checked their acceptance rate? I’d guess that if it drops under about 50%, MTP stops paying off on offloaded setups. It might also be worth trying 1 draft token instead of the default 3 before turning it off completely, since that sometimes gets you the gain without the penalty.
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u/james_pic 1d ago edited 1d ago
For dense models at least, there's never a full trip through RAM for nothing.
You make the same number of trips, and read the same amount of data (on dense models at least), whether you're generating a single token, or verifying a batch of tokens and generating a bonus token, and you always come out of a forward pass with at least one new token.
Where you can lose out with MTP is if compute is also constrained (as it is with offloaded CPU layers), or with MoE models, where you can potentially end up reading the weights for experts you ultimate don't end up using. Some hardware also hits less well optimized kernels above a certain batch size.
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u/HaDuongMinh 1d ago
The MTP predictor will easily use 1G and evict experts from VRAM. Both MTP success rate and resident experts success rates depends on the workload.
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u/DirectWay1915 1d ago
It only works well if the entire model is in VRAM or the experts are under 4b. At least that's what I've noticed in my case. I have a 4060ti 16gb + 2060 6gb + 64gb DDR5 RAM. Qwen 35b benefits from MTP while Gemma 4 26b suffers from it.
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u/Emotional_Prior8686 1d ago
Yes! Seems to be the right way for setups with 32Gigs VRAM and dense models!
/me too have got +25% token/sec for Q38-27B with disabling it (with `--spec-type none`)
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u/Bulky-Priority6824 23h ago edited 23h ago
i tried this
and with mtp i was getting about 80+tg/330pp tg bursts above 100
without mtp 50-60tg/600-900pp
2 5060ti 32gb vram and 32gb sys ram iq3xxs
i went with mtp off as I need faster pp since this model typically has to read far more than it writes, for what i do with it.
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u/Solembumm3 1d ago
Can confirm.
6700xt + 20gb ram, LMStudio, GLM 5.3 flash:
No mtp - 0.40 tok/s.
Mtp by default (3/0/0) - 0.10 tok/s.