AI · GPU infrastructure
How AI compute actually gets built.
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Microsoft and Alphabet both undershot Q3 capex estimates, and neither cut demand. The real story is neocloud delivery slips, Alphabet's TPU inventory build, and a Q4 that has to be the biggest quarter of the cycle.
Tom Pechulis, , 5 min read
, 5 min read
An 8-GPU HGX node and a 72-GPU NVL72 rack look like the same idea at different sizes. They aren't. Here's what actually changes in the NVLink domain, the network, power, cooling, and how you plan a deployment.
, 4 min read
How many GPUs fit in a 100 MW data center? A simple, honest model from utility power to GPU count, with the assumptions spelled out so you can swap in your own.
, 4 min read
Vera Rubin NVL72 pulls up to 227 kW per rack, and Kyber is headed further. At 54 V that's more than 4,000 amps of busbar. Why the industry is moving to 800 VDC, what changes in the facility, and the economics behind it.
, 4 min read
Amazon, Alphabet, Microsoft, and Meta guided to roughly $720–745B of 2026 capex. Capex now exceeds operating cash flow at two of them. A look at the numbers, the accounting quirks, and what to watch going into Q3 prints.
, 4 min read
NVIDIA's Spectrum-X Photonics hit full production in August. Why moving the optics onto the switch package matters for power, reliability, and the supply chain, and the CPO-vs-NPO fight coming for Rubin Ultra scale-up.
, 4 min read
H100 rental prices went up in 2026, not down. A bottoms-up model of $/GPU-hr for a GB200 build, CoreWeave's P&L as a case study in depreciation and interest, and why $2.50 vs $3.50 is the line between a dud and a deal.
, 4 min read
Same GPUs, very different clusters. Training is a synchronized throughput problem. Inference is a memory-bandwidth and KV-cache problem, which is why prefill/decode disaggregation is taking over. The math, with Llama 3 70B as the example.
, 4 min read
Meta's Llama 3 run hit an interruption every ~3 hours on 16K GPUs. At 100K GPUs, checkpoint and restart time decide your goodput. A worked model of checkpoint size, bandwidth, and optimal interval, plus what it costs when you get it wrong.
, 4 min read
A worked example of sizing an 8,192-GPU scale-out fabric: rails, radix, oversubscription, switch counts, and the optics bill nobody budgets for.
, 3 min read
GPU supply gets the headlines, but memory is the gating item. SK hynix just posted a 76% operating margin, Micron is booked through 2027, and Amazon raised capex because memory got expensive. What that means for how you plan clusters.
, 4 min read
Quantum-X800 InfiniBand and Spectrum-X Ethernet both ship 800 Gb/s AI fabrics. Ethernet is winning on share, InfiniBand is having a rebound, and the right answer depends on operations, tenancy, and how much you value SHARP.
, 5 min read
The average data center rack still pulls about 9 kW. A GB200 NVL72 pulls 120+. Here's the physics, the facility changes, and the money behind direct-to-chip liquid cooling.