One month coding with GLM 5.3 Flash (wagtail.org)

66 points by ThibWeb 6 hours ago

epistasis 2 hours ago

One thing about these numbers that's absolutely shocking to me is how low the energy use is:

> That model’s usage was well within our budget ($68, about 4kWh of energy use / 365 grams of carbon emissions).

The energy cost is literally 1% of the total cost. For context, 4kWh of energy would drive you about 15 miles in an EV, about half of the average person's daily driving miles. It's boiling 10 gallons of water.

With the talk of AI data centers' impact on the world, you'd think this would be 10x to 100x the amount of energy in order to get the effects they're using here.

My takeaway: the AI data center buildout is an overbuild probably at least as large as the fiber buildout that left us with so much dark fiber. If not even bigger. The only thing that will save the economy is the inability of NVIDIA and chip fabs to produce enough chips to match the buildout planned.

ThibWeb 2 hours ago

I agree but it does worry me how fast my usage is increasing. Two months ago I was using 10x less tokens and probably not much more than 5kWh on inference. This month about 30kWh on inference. If it becomes more affordable, is there going to be another jump? Not quite sure

CuriouslyC 31 minutes ago

At some point the agents will be good enough that you can tell them "here's $100, go make me money" and they will, maybe not a lot and not all the time, but the EV given the cost of inference will be positive.

mannanj a minute ago

pphysch 10 minutes ago

smartmic an hour ago

Related to this: see the difference between China and US here: https://aidatacenterindex.com/compare/united-states-vs-china...

I have the feeling China is somehow ahead when it comes to energy (and cost) efficiency for AI usage. After all, the two are in a direct competition, and this difference is significant. Or is the "hyper" scaling of energy hungry datacenters in US part of a bubble?

killingtime74 an hour ago

Your only talking about variable direct energy. Does it take into account the entire lifecycle, building the data centre, running the cooling, building the chips, the % the chips are not utilised.

epistasis 10 minutes ago

> Does it take into account the entire lifecycle, building the data centre

My entire point is that 99% of the dollar cost of running these models goes to things other than the GPU power. The capex cost to building cost to GPU cost to storage/networking/chasses/wiring plus the other operation costs dwarf the electricity. Even the other electricity costs, lets say double it for all the supporting compute, plus another 25% for a 1.25 PUE, and you're at 2.5% of all-in cost of running these models is from electricity.

The non-electricity costs are massive and the constraints on fabs, etc. will drive the amount of the AI build far more than energy availability.

ThibWeb 38 minutes ago

No those numbers are GPU only. See https://cleerdash.sustainableaigroup.com/ for a fuller model

eli 39 minutes ago

It would be a pretty big deal if the average person's car became 50% less energy efficient, no?

aktenlage 2 hours ago

> Unfortunately there are still consequences to it. I chose the 'wrong' model for the prototype, and we spent 450M tokens / $150 / 5kWh of energy use almost overnight. The MCP server itself works well and we now have a great demo of the capabilities, so it’s not for nothing:

> Nonetheless, it’s a good reminder to be careful with model selection and with agentic patterns. We could have achieved similar results for most likely 5x less cost with not that much more effort. Lessons learned! We need to budget for this, and be more careful. Could have seen it coming, but now we know.

I don't get it. Why was it wrong? Which one would have been better? What was the lesson and how could you have foreseen it?

ThibWeb 2 hours ago

Hmm I might need to rephrase. Initial challenge was to use GLM 5.3 Flash and I was on the non-Flash version for the whole vibe coded build. Just wasn’t paying attention and I didn’t realize that one session was a quarter of the month’s spend and 150% of the budget (big price difference between models)

sheepscreek 21 minutes ago

> 450M tokens / $150 / 5kWh

Makes me appreciate my ChatGPT subscription. I’ve had multiple days between 1B-2B tokens (now less so, models have indeed become token efficient) and regularly in the > 100M range. Even then, $150 sounds excessive. I wonder if their cache is getting nuked for some reason, or maybe they decide to use Cerebras that doesn’t subsidize cached tokens.

monksy 2 hours ago

GLM5.3-flash has been fantastic for me to make minor fixes in ambigious ways. "Fix x feature, whats going wrong. " It does the job.

surgical_fire 2 hours ago

GLM-5.3-flash is my implementation model after GLM-5.3 writes the plan.

It's an excellent workhorse. When I am running out of my GLM quota I switch GLM-5.3-flash to DS-4.1-flash.

disiplus 2 hours ago

Was this post generated with LLM, did he properly mention anywhere why exactly did it fail with example or i have trouble reading.

desmondl 14 minutes ago

Yeah, I clicked expecting a review of GLM 5.3 Flash, but the article was more a retrospective about what he learned during his September challenge: "Only use GLM 5.3 Flash for one month"

He said his experiment was a failure because:

1. He accidentally spent 450M tokens vibe coding with the wrong model, instead of GLM 5.3 Flash.

2. When he used GLM 5.3 Flash, it was sometimes slow. So he switched to other models (Deepseek / Qwen) instead. His guess to why it was slow: GLM 5.3 Flash was so good that the providers were congested.

3. He still needed to use other models besides GLM 5.3 Flash, for R&D and benchmarking.

His takeaways from doing the experiment were:

1. Measure local usage more.

2. Experiment with agent orchestration, with bounded goals.

3. Don't count other models that are used for R&D.

4. Play with Jev.

5. Include experiments with flagship models to compare with cheap open models.

His conclusion about GLM 5.3 Flash: Probably viable for day to day work, but he'll have more thoughts next month.

raggi 14 minutes ago

Some vague commentary about performance with what appears to be assumptions about GPU availability, but no clarity about which inference provider is being used. If ZAI is assumed, I believe they aren't subject to the assumptions in the post based on what they've said publicly, but if they were using some other provider, perhaps.

The second reason appeared to be simply "because we chose not to". The post seems to be pretty much content-less in any practical sense. I clicked on it because I do quite like this models average performance and I was hoping to see some kind of review content.

ThibWeb 6 hours ago

It was a bit of a silly challenge, wasn’t sure how workable, learned a lot in the process about what actually drives usage / costs, and how to keep both under control

cvburgess 6 hours ago

Considering they were your top two models, how did the flash and non-flash versions compare? Did you use them for different tasks?

RussianCow an hour ago

Not OP, but I've used both quite a bit and I think GLM 5.3 (non-flash) is a vastly better model. The flash variant is good for general workhorse agents, but it doesn't seem to reason holistically about code and over-engineers solutions to each specific problem it solves. But if you use GLM 5.3 to write a detailed plan with little to no ambiguity, GLM 5.3 Flash executes it just fine for a fraction of the price.

ThibWeb 2 hours ago

I have a hard time justifying GLM 5.3 these days. It’s slightly better than Flash but rarely enough to justify the much steeper price. We chose to use usage-based billing only so are very sensitive to model price.

gunalx 2 hours ago

When text wuality or for pure but adwansed coding is concerned i always pick glm 5.3. The flash is awesome for everything that dosent really matter though.

sampullman 3 hours ago

Worth a comparison with DeepSeek v4.1 flash, if you've got another month to spare!

nowittyusername 2 hours ago

Ill tell you from my personal use glm 5.3 flash was better then deepseek 4.1 flash, also deepseek liked to yap in his reasoning traces soo fucking much, the yapping was fast but the task was so slow to complete...

RussianCow an hour ago

ThibWeb 2 hours ago

Yep, I think next month will be on that. It feels slightly better from a few days of use, and in our WIP benchmarking it scores way higher

samtheprogram 2 hours ago

DS v4.1 Flash is roughly equivalent. It's going to get some things right/better that GLM flash doesnt and vice versa.

lnenad 2 hours ago

They've got an image of their homegrown benchmark in the post that lists DS4.1.

gpugreg 2 hours ago

How did you measure energy usage?

Edit: I found a linked article that mentions the inference provider who does the measurements.

ThibWeb 2 hours ago

Yes, all from Neuralwatt, GPU energy use only. Makes models’ “efficiency” much more visible than tokens.

throw930rmdkdk 3 hours ago

Flash is pretty decent coder, but it should be paired with good planner and reviewer. I would pick astra low for planning and sol 6.1 medium for reviews.

eikenberry 3 hours ago

What would you use if you wanted to stay (at least) open weight?

verdverm 2 hours ago

qwen3.8, kimi3, kimi2.7, GLM-5.3 are all good families I use in my coding team

I'm mainly using flash varients, at least as the default, bump.up to stronger model as needed (less often these days)

Geof25 2 hours ago

esafak 2 hours ago

Deepseek 4.1 Flash and Mimo 2.6 Flash.

esafak 2 hours ago

Flash is plenty good for planning and reviewing, for my needs. In fact, I use it for that because it's too slow for execution, despite the name.

edit: I subscribe to z.ai, I don't host.

jminnl 2 hours ago

> I use it for that because it's too slow for execution

What kind of hardware and what particular quant?

gunalx 2 hours ago

Will agree on this. From z.ai i have found the non flash to have way more consistent performance.

benjiro29 an hour ago

There are some issue point not properly mentioned ...

* Models like DeepSeek V4.1 Flash are much cheaper on DeepSeek their API directly because of the cache handeling is better. Neuralwatt can hit up to 98% but DeepSeek can do 99.x... That may not sound like a big difference but it quickly widens the gap on long tasks to grow 2x a 3x in price. DeepSeek their cache handeling is S-tier (with a ton of features, for instance 24h caching).

* The same issue is also present if you compare GLM 5.3 Flash with z.ai vs Neuralwatt. Its just way more cheaper from the source, then from Neuralwatt.

* The energy numbers from Neuralwatt are ... to be taken with a ton of salt. Past energy numbers had the same models (for instance) GLM 5.2 up to 6x cheaper in energy usage, then after they "fixed" issues with the energy numbers. In reality, those energy numbers are just a different form of billing, but not a actual representation of the energy usage of AI models. Things like profits are inside those energy numbers. So seeing 4kWH used for a model, does not mean that it uses 4Kwh.

Edit: That are some interesting downvotes ...

To answer the questions. It was stated by the CEO himself in one of the video blogs that the energy prices inc their profit margins. Regarding their published numbers ... I like to point out that this is the same company that had up to 6x cheaper energy numbers at the start of the year until they got updated. Again, its in one of those video blogs the CEO did. Its around the same time when they increased the price from $5/1kwh to $10/1kwh.

Yes, DeepSeek API is cheaper then Neuralwatt. I have done way too many comparisons between NW and other providers, regarding their prices. Over long sessions, that gap grows because of the differences in caching. You need to use the NW Flex option to reduce the impact but then your constantly waiting on responses (good for overnight work, not great in prime time).

Edit 2: I am getting a little bit fed up with the people who downvote and do not give their reasons for the downvotes.

ThibWeb 40 minutes ago

For what it’s worth the energy numbers I get from Neuralwatt are within the ballpark of what is available elsewhere like https://cleerdash.sustainableaigroup.com/. What’s your source that there is profit / capex in there? Their published methodology seems pretty transparent

eli 43 minutes ago

I'm skeptical that the DeepSeek official API actually nets out cheaper right now, but I avoid it anyway because they store and train off of your prompts.

I think NW's profits are mostly between what they pay for electricity and what they charge you for electricity. I don't think there's any need to look to conspiracies to explain billing errors.